Flow immunoassay scanning assembly

ABSTRACT

Methods and assemblies are provided for scanning a flow immunoassay assembly. A flow immunoassay scanning assembly includes a plurality of immunoassay reaction chambers, a plurality of read cells in fluid communication with the plurality of immunoassay reaction chambers, a detector having a sensing beam, and a scanning drive assembly configured to translate the detector to intersect the plurality of read cells with the sensing beam. The detector includes an optical detector, and each of the immunoassay reaction chambers contains fluorescent labeled antigen that is displaced when an analog to the fluorescent labeled antigen flows through the immunoassay reaction chamber. Thus, the fluorescent labeled antigen can be detected by the optical detector when flowed through the corresponding read cell. The detector can also be configured, such that the sensing beam intersects the plurality of read cells at an angle substantially perpendicular to the longitudinal axes of the read cells. The scanning drive assembly can be configured to translate the detector to repeatedly intersect the plurality of read cells with the sensing beam.

RELATED APPLICATIONS

[0001] The present application claims priority under 35 U.S.C. 119(e) toU.S. Provisional Application No. 60/336,596 filed Dec. 4, 2001, which isincorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

[0002] The present inventions generally relate to systems, methods, anddevices for the identification of analytes in bodily fluids, and inparticular, for the identification of drugs, alcohol, and other toxicsubstances in saliva.

BACKGROUND OF THE INVENTION

[0003] The collection of body fluids for diagnostic analysis has longbeen used in medical, diagnostic, forensic, veterinary medical and otherfields to test and monitor for the presence of specific molecules withinthe fluid. Results of such analyte testing can be used to diagnosemedical conditions, and to measure the concentration of pharmaceuticaland other drugs or toxic substances in a human or animal subject.Analyte test results can also be used to monitor appropriate levels oftherapeutic agents, or for other purposes. A subject's oral fluids maybe used to test for a wide variety of types of molecules whoseconcentration in saliva is related to the circulating concentration ofthose molecules or related metabolites of substances in the blood.(Malamud, D, Saliva as a diagnostic fluid, Br. Med. J., 305, 207-208(1990); Mandel, I. D, The diagnostic uses of saliva, J. Oral Pathol.Med., 19, 119-125 (1990); Mandel, I. D., Salivary Diagnosis: Promises,Promises, Malamud, D. and Tabak, L. (eds.); Saliva as a DiagnosticFluid, Vol. 694: Annals of the New York Academy of Sciences, New York:The New York Academy of Sciences (1993), pp. 1-8).

[0004] Use of saliva as a medium for analysis is desirable since it canbe obtained by noninvasive methods, unlike blood product collectionmethods that involve trained medical personnel and use venipuncture orfinger-stick methods of collection. Oral fluid collection can also bedone in public without requiring privacy booths, bathroom facilities,and careful subject monitoring otherwise required to avoid adulteration,sample replacement, sample dilution and other problems associated withurine collection. A number of sample collection assemblies and methodshave been disclosed. For example, U.S. Pat. No. 6,022,326 issued toTatum et al., which is fully and expressly incorporated herein byreference, describes a device and method for automatically collectingsaliva from a subject through aspiration using a wand with an associatedsaliva collection tip and a vacuum that flows the saliva from the tip,through the wand, and into a collection chamber. After the saliva sampleis collected, it is typically sent to a specialized laboratory foranalysis.

[0005] Many different assay methods for measuring an analyte in a sampleare known in the art. Many of such methods are immunological based,i.e., they involve measuring the binding of an antibody or antibodyfragment to a complementary ligand, e.g., a drug or other molecule.Immunoassay methods, in general, are based on the competition between aspecific analyte, the concentration of which is to be measured in asample, and a known amount of tracer, which is generally the analyte oran appropriate analog antigen thereof in labeled form, with the analyteand tracer competing for a limiting number of available binding sites ona binder. U.S. Pat. Nos. 5,183,740 and 5,354,654 issued to Ligler etal., which are hereby fully and expressly incorporated herein byreference, disclose these immunoassay methods in further detail.

[0006] Typically, semi-automated or automated systems are used to loadand perform immunoassay tests on the saliva samples. The majority of thesystems on the market comprise a loading tray for loading multiplesamples, which are not necessarily of the same nature or having the sameassay performed on them. There is also a reagent tray that holds anumber of reagent cartridges for the various different tests to beperformed. In the machine, the samples are transferred, normally bypipetting into an assay cell, where the sample is combined with thenecessary reagent or reagents. The assay cell is then transferred to apart of a machine where it can be held for sufficient time for thereagent and the sample to combine. Thereafter, the sample cell istransferred to the detector, which detects the presence of a knownindicator to determine whether or not the sample contained a particularcomponent and/or how much of that component was present in the assay.

[0007] Recent systems have employed flow injection technology, whichinvolves combining the sample in a fluid stream that passes through areaction column containing a support medium on which antibodies arebound and saturated with a labeled antigen. The fluid stream passes overthe support media, where competition between any analytes and thelabeled antigen occur. Any displaced labeled antigen passes out throughthe reaction chamber and into a transparent detection chamber where itis detected and quantified, e.g., by fluorescent means, as an indicationof the presence and quantity of the specific analyte to be tested. U.S.Pat. Nos. 5,370,842, 5,779,978, 6,120,734, 6,159,426, as well aspreviously mentioned U.S. Pat. No. 5,183,740, discuss this flowinjection technology in some detail.

[0008] The above-described methodologies are sufficient for someapplications, e.g., those applications in which time is not critical.For other applications that require portability and/or real-time testingof the sample, e.g., in police stations, emergency rooms, etc., sendinga sample to a laboratory for analysis is simply not practical. Inresponse to the need to decrease the amount of time required to obtaintest results from a sample, as well as the need to provide moreconvenient and less expensive diagnostic methods, there have beenefforts to develop simple tests to allow unskilled persons to performcertain analytical procedures outside of the laboratory. For example,U.S. Pat. No. 5,145,789 describes a method for testing urine. Aspreviously mentioned, however, there are various problems that areassociated with urine collection and testing.

[0009] Other methods, such as those described in U.S. Pat. Nos.4,703,017, 5,556,789, and 5,714,341, require a two-step process, whichinvolves collecting the specimen, and then manually applying thecollected specimen to the analytical device. Thus, at least twooperations and devices are necessary with these previous methods. First,collection of the saliva specimen with some type of collection deviceand, second, application of the saliva specimen to the analytical devicedescribed in those inventions. Thus, these methods are disadvantageousin that they are not performed in real time and requires additionalhandling by users, posing a risk that errors may be unknowinglyintroduced into the test results.

[0010] U.S. Pat. No. 6,248,598 describes a method that collects thesaliva and initiates an assay or assays of the saliva in one step. Thismethod, however, requires the use of a saliva absorption technique,which has significant limitations, including slow collection times, riskof irreversible absorption into the carrier membrane, inability toobtain quantitative results, and a limitation of the number of differenttests that can be performed on the small sample size.

[0011] There thus remains a need for improved systems, methods, andassemblies that test or facilitate in testing bodily fluids for targetanalytes, e.g., drugs in saliva.

SUMMARY OF THE INVENTION

[0012] Tester for Automated Identification of Analytes in Bodily Fluids

[0013] The present inventions are also directed to systems, methods, andassemblies for identifying one or more analytes within bodily fluids,such as saliva.

[0014] In accordance with a first aspect of the present inventions, asystem comprises an analyte tester, an oral aspirator, a conduit that isin fluid communication between the oral aspirator and the tester, and apump in fluid communication with the conduit. In this manner, theaspirated oral fluid can be pumped directly from the aspirator into theanalyte tester for identification of one or more oral fluid analytes. Ina non-limiting preferred embodiment, the analyte tester can be a flowimmunoassay tester that identifies the five NIDA drugs-of-abuse, and canbe configured to identify up to ten different drugs or other analytes.The analyte tester can also be portable, so that it can be convenientlyused areas remote from laboratories. The tester may comprise a chemistrycassette and a test console configured for receiving the chemistrycassette. In this case, the conduit may be in fluid communication withthe chemistry cassette. A user interface may also be provided forentering test information (e.g., a specific test selection or test panelcustomization) and for conveying test results (e.g., using a display orprinter).

[0015] In accordance with a second aspect of the present inventions, asystem comprises an analyte tester that is configured to identify one ormore analytes in less than 1 ml of bodily fluid, a sample collectioninterface device, a conduit that is in fluid communication between thesample collection interface device and the tester, and a pump in fluidcommunication with the conduit. In this manner, the system can beconveniently used to test for analytes in a subject without the use of asubstantial amount of bodily fluid. In a non-limiting preferredembodiment, the pump may be configured for pumping bodily fluid throughthe conduit at a rate of less than 200 μL/min. Although other types ofbodily fluid can be collected, the sample collection interface devicecomprises an oral aspirator for collecting saliva from the test subjectin the preferred embodiment. Other previously described features canalso be incorporated into an embodiment constructed in accordance withthe second aspect of the present inventions.

[0016] In accordance with a third aspect of the present inventions, amethod comprises pumping an oral fluid sample from a subject to ananalyte tester, and identifying one or more analytes contained in theoral fluid sample. In a non-limiting preferred method, a flowimmunoassay technique can be used to semi-quantitatively orquantitatively identify the five NIDA drugs-of-abuse, and can bemodified to test up to ten different drugs or other analytes. The samplecan be aspirated from the test subject, and the time that it takes tocomplete the method can take less than ten minutes.

[0017] In accordance with a fourth aspect of the present inventions, amethod comprises pumping less than 1 ml of a bodily fluid sample from asubject to an analyte tester, and identifying the one or more analytescontain in the sample. In a non-limiting preferred method, the samplecan be pumped at a rate of less than 200 μL/min. Although other types ofbodily fluid can be pumped from the test subject, oral fluid can be usedas the sample. Other previously described features can also beincorporated into a method performed in accordance with the fourthaspect of the present inventions.

[0018] In accordance with a fifth aspect of the present inventions, acassette assembly comprises a chemistry cassette receivable within atest console, and a bodily fluid sample collection assembly configuredfor being in fluid communication with the chemistry cassette. Thechemistry cassette enables the test console to identify one or morebodily fluid analytes. In a non-limiting preferred embodiment, thechemistry cassette can be a fluid immunoassay cassette, and the bodilyfluid sample collection assembly can be an oral fluid sample collectionassembly that includes an oral aspirator, sample collection chamber, anda conduit in fluid communication between the oral aspirator and thesample collection chamber.

PLUNGER-BASED FLOW IMMUNOASSAY ASSEMBLY

[0019] The present inventions are also directed to assemblies andmethods for flowing sample through a flow immunoassay assembly using oneor more plungers.

[0020] In accordance with a first aspect of the present inventions, aflow immunoassay assembly comprises an immunoassay reaction chamber, asample distribution chamber in fluid communication with the immunoassayreaction chamber, and a sample dispense plunger being movable within thesample distribution chamber to dispense the sample from the sampledistribution chamber into the immunoassay reaction chamber.

[0021] In a non-limiting preferred embodiment, the flow immunoassayassembly can further include a buffer chamber in fluid communicationwith the immunoassay reaction chamber, and a buffer dispense plungermovable within the buffer chamber to dispense buffer from the bufferchamber into the immunoassay reaction chambers. The preferred flowimmunoassay assembly can further include a read cell in fluidcommunication with the immunoassay reaction chamber for providing ameans to measure a reaction within the reaction chamber (which may be adisplacement type immunoassay reaction chamber) and a waste chamber influid communication with the read cell for storage of hazardousbiological fluid. Upper and lower seals can be provided on the bufferchamber for storage of the buffer prior to use, in which case, thebuffer dispense plunger can be provided with a stylus that is configuredto puncture the upper seal when the buffer dispense plunger is movedtoward the upper seal. To automate the preferred immunoassay flowassembly, it can further include a drive assembly mechanically coupledto the sample dispense plunger, and if applicable, the buffer dispenseplunger.

[0022] In accordance with a second aspect of the present inventions, aflow immunoassay assembly comprises a plurality of immunoassay reactionchambers, a plurality of sample distribution chambers in fluidcommunication with the plurality of immunoassay reaction chambers, and aplurality of sample dispense plungers being movable within the pluralityof sample distribution chambers to dispense the sample from theplurality of sample distribution chambers into the plurality ofimmunoassay reaction chambers.

[0023] In a non-limiting preferred embodiment, the flow immunoassayassembly can further include many of the other features described above,such as buffer chambers, read cells, a waste chamber, and a driveassembly, but can also comprise other features that facilitate themultiple flow paths. For example, the preferred flow immunoassayassembly can include a valve, such as a rotary valve, to selectivelyplace the plurality of sample distribution chambers in fluidcommunication with the plurality of immunoassay reaction chambers, andif applicable, the plurality of buffer chambers in fluid communicationwith the plurality of immunoassay reaction chambers. The preferred flowimmunoassay assembly can further include a sample/buffer mixing assemblyin fluid communication with the plurality of sample distributionchambers, in which case, the mixing assembly is configured for mixingsample and buffer to form a buffered sample solution and distributingthe buffered sample solution amongst the sample distribution chambers.The number of sample flow paths, i.e., the number of sample distributionchambers and corresponding immunoassay reaction chambers, can equal fiveor more, or even ten or more. Similarly, if applicable, the number ofbuffer flow paths, i.e., the number of buffer chambers and correspondingimmunoassay reaction chambers, can equal five or more, or even ten ormore.

[0024] In accordance with a third aspect of the present inventions, amethod of analyzing a sample comprises distributing the sample into aplurality of sample distribution chambers, flowing the sample from theplurality of sample distribution chambers through a plurality ofimmunoassay reaction chambers by moving a plurality of sample dispenseplungers within the plurality of sample distribution chambers, andmeasuring a reaction with each of the plurality of immunoassay reactionchambers. In a non-limiting preferred method, buffer can be flowed froma plurality of buffer chambers through the plurality of immunoassayreaction chambers by moving a plurality of buffer dispense plungerswithin the plurality of buffer chambers. The buffer can be flowedthrough the plurality of immunoassay reaction chambers prior to, during,after the sample flow, and even during sample distribution. The sampleflowing through the plurality of immunoassay reaction chambers canproduce a analyte detectable sample solution, in which case, thepreferred method can further comprise flowing the analyte detectablesample solution through a plurality of read cells and measuring ananalyte indicator, such as a labeled antigen, in the analyte detectablesample solution. The sample tested can be bodily fluid, such as saliva.

AUTOMATED PLUNGER-BASED SAMPLE/BUFFER MIXING ASSEMBLY

[0025] The present inventions are also directed to assemblies andmethods for mixing a sample and a buffer.

[0026] In accordance with a first aspect of the present inventions, asample/buffer mixing assembly comprises a sample collection chamber, abuffer chamber containing a buffer, a mixing chamber, and one or moreplungers. The sample collection chamber is in fluid communication with asample collection interface device. The mixing chamber comprises asample port adjacent the sample collection chamber, and a buffer portadjacent the buffer chamber. The one or more plungers is in fluidcommunication with the sample collection chamber and the buffer chamber,and can be moved to dispense the buffer from the buffer chamber into themixing chamber via the sample port, and the sample from the samplecollection chamber into the mixing chamber via the buffer port. In thismanner, the dispensed sample and buffer form a buffered sample solutionwithin the mixing chamber.

[0027] In a non-limiting preferred embodiment, the one or more plungerscan include a buffer dispense plunger that is movable within the bufferchamber towards the buffer port to dispense the buffer from the bufferchamber into the mixing chamber under positive pressure via the bufferport. The one or more plungers can also include a sample dispenseplunger that is movable within the mixing chamber away from the sampleport to dispense the sample from the sample collection chamber into themixing chamber via the sample port. The preferred sample/buffer mixingassembly can be automated by mechanically coupling drive assemblies tothe sample and buffer dispense plungers. To ensure that the sample andbuffer are mixed, a ferrous element can be provided within the mixingchamber, and a mixing motor can be magnetically coupled to the ferrouselement to agitate the buffered sample solution. The preferredsample/buffer mixing assembly can also be used to mix saliva and buffer,in which case, the sample collection chamber is a saliva collectionchamber.

[0028] In accordance with a second aspect of the present inventions, amethod of buffering a sample comprises dispensing the sample into amixing chamber via a sample port, dispensing buffer into the mixing viaa buffer port, and mixing the sample and the buffer in the mixingchamber to form a buffered sample solution. Sample and buffer chambersare moved in fluid communication with the mixing chamber to dispense thesample and buffer within the mixing chamber.

[0029] In a non-limiting preferred method, the buffered sample solutionmay be dispensed from the mixing chamber via a dispense port by movingbuffered sample dispense plunger in fluid communication with the mixingchamber, e.g., by moving the buffered sample dispense plunger within themixing chamber towards the dispense port. The buffered sample solutioncan be mixed within the mixing chamber simply through the dispensingprocess, or additionally by a mixing motor. The preferred method can beautomated by mechanically coupling drive assemblies to the sample andbuffer dispense plungers.

[0030] In accordance with a third aspect of the present inventions, amixing assembly comprises a first chamber containing a first solution, asecond chamber containing a second solution, and a third chambercomprising a first port in fluid communication with the first chamber, asecond port in fluid communication with the second chamber, and a thirdport. The mixing assembly further comprises a first plunger disposedwithin the first chamber, which is movable to dispense the firstsolution from the first chamber into the third chamber via the firstport. The mixing assembly further comprises a second plunger disposedwithin the third chamber, which is movable to dispense the secondsolution from the second chamber into the third chamber via the secondport to form a fluid mixture with the first and second solutions. Themixing assembly further comprises a third plunger disposed within thethird chamber, which is movable to dispense the fluid mixture from thethird chamber via the third port.

[0031] In a non-limiting preferred embodiment, the mixing assembly canbe a sample/buffer mixing assembly, wherein the first, second, and thirdchambers can be buffer, sample collection, and mixing chambers, thefirst and second solutions can be buffer and sample, the first, second,and third ports can be buffer, sample, and dispense ports, and thefirst, second, and third plungers can be buffer, sample, and dispenseplungers. The buffer port can have a seal to hold the buffer within thebuffer chamber. In this case, the buffered sample dispense plunger canbe provided with a stylus that punctures the seal when the bufferedsample dispense plunger is moved towards the buffer port. The dispenseport can also be provided with one or more through ports for allowingthe buffer to flow from the buffer chamber into the mixing chamber. Thebuffer dispense plunger can be mated with one side of the bufferedsample dispense plunger to move the buffered sample dispense plungertowards the dispense port, and the sample dispense plunger can be matedwith the other side of the buffered sample dispense plunger to move thebuffered sample dispense plunger towards the buffer port to puncture theseal. The mixing chamber can be in axial alignment with the bufferchamber to allow the buffer dispense plunger to engage the bufferedsample dispense plunger within the mixing chamber. The buffer chambercan also have a plug that is receivable within the through port of thebuffered sample dispense plunger to prevent leakage when the bufferedsample dispense plunger is moved towards the dispense port to dispensethe buffered sample solution. The buffer port may be a longitudinal portand the sample port may be a lateral port, in which case, one surface ofthe buffered sample dispense plunger may be adjacent the buffer port andthe opposite surface of the buffered sample dispense plunger may beadjacent the sample port. Other previously described features can alsobe incorporated into an embodiment constructed in accordance with thesecond aspect of the present inventions.

[0032] In accordance with a fourth aspect of the present inventions, amethod of mixing first and second fluid using first, second, and thirdchambers comprises a disposing the first fluid in a first chamber, anddisposing the second fluid in a second chamber. The method furthercomprises moving the first plunger within the first chamber towardsfirst port to dispense the first solution from the first chamber intothe third chamber, moving a second plunger within the third chamber awayfrom a second port to dispense the second solution from the secondchamber into the third chamber to form a fluid mixture from the firstand second solutions, and moving a third plunger within the thirdchamber towards the third port to dispense the fluid mixture from thethird chamber out through the third port.

[0033] In a non-limiting preferred embodiment, the first, second, andthird chambers can be buffer, sample collection, and mixing chambers,the first and second solutions can be buffer and sample, the first,second, and third ports can be buffer, sample, and dispense ports, andthe first, second, and third plungers can be buffer, sample, anddispense plungers. The buffered sample dispense plunger can also be usedto puncture a seal on the buffer port prior to dispensing the bufferinto the mixing chamber. The buffered sample dispense plunger can bemoved towards the dispense port by pushing it with the buffer dispenseplunger, or moved towards the buffer port by pushing it with the sampledispense plunger. The sample and buffer can be simultaneously dispensedinto the mixing chamber by moving the sample and buffer dispenseplungers simultaneously. Other previously described features can also beincorporated into an embodiment constructed in accordance with thesecond aspect of the present inventions.

HYDROPHOBIC/HYDROPHILIC SAMPLE COLLECTION TIP

[0034] The present inventions are also directed to assemblies forcollecting oral fluid from a mouth of a subject using ahydrophobic/hydrophilic sample collection tip.

[0035] In accordance with a first aspect of the present inventions, asample collection assembly comprises a sample collection tip configuredfor being placed within the mouth, and a conduit in fluid communicationwith the sample collection tips. The sample collection tip comprises ahydrophobic interior and a hydrophilic outer surface. In this manner,the tendency of analytes within the sample to stick to the interior ofthe sample collection tip is minimized, while allowing wetting of theouter surface of the sample collection tip with the sample to facilitateits collection.

[0036] In a non-limiting preferred embodiment, the sample collectionassembly can further include a hand piece that has a tip on which thesample collection tip is mounted, and through which the conduit canextend. The sample collection tip can have a bore in which the conduitis disposed, e.g., by bonding. The hydrophobic interior of the samplecollection tip can be composed of a microporous material, such as highdensity polyethylene, and the hydrophobic outer surface of the samplecollection can comprise a surfactant. The sample collection tip can haveany suitable shape, e.g., hemi-dome shaped.

[0037] In accordance with a second aspect of the present inventions, asample collection assembly comprises a sample collection tip configuredfor being placed within the mouth, and a conduit in fluid communicationwith the sample collection tips. The sample collection tip comprises ahydrophobic body and a hydrophilic surfactant disposed on an outersurface of the hydrophobic body. In a non-limiting preferred embodiment,the afore-described features can be incorporated into the samplecollection assembly.

[0038] In accordance with a third aspect of the present invention, asample collection assembly comprises a sample collection tip configuredfor being placed within the mouth, a sample collection chamber, aconduit in fluid communication with between the sample collection tipand the sample collection chamber, and a pump configured to pump samplefrom the sample collection tip, through the conduit, and into the samplecollection chamber. The sample collection tip comprises a hydrophobicinterior and a hydrophilic outer surface, which facilitates the wettingof the entire outer surface of the sample collection tip, therebyfacilitating pumping of the sample. In a non-limiting preferredembodiment, the afore-described features can be incorporated into thesample collection assembly. Additionally, the pump can use relativelylow air flow rates, e.g., between 5-50 ml/min at 350 mmHg absolute, topump the sample.

METHOD FOR ACCURATELY MIXING SAMPLE AND BUFFER SOLUTIONS

[0039] The present inventions are also directed to methods foraccurately mixing two solutions, e.g., buffer and sample solutions.

[0040] In accordance with an aspect of the present inventions, a methodof mixing first and second fluids using first, second, and thirdchambers comprises selecting a fluid mixture r, providing the firstchamber with a first cross-sectional area A₁, providing the thirdchamber with a second cross-sectional area A₂, disposing the first fluidin the first chamber, disposing the second fluid in the second chamber,moving a first plunger within the first chamber at a speed S₁ towards afirst port to dispense the first solution from the first chamber intothe third chamber, and moving a second plunger substantiallysimultaneously with the first plunger within the third chamber at aspeed S₂ away from the second port to dispense the second solution fromthe second chamber into the third chamber, wherein A₂S₂=A₁S₁(1+1/r).

[0041] In a non-limiting preferred method, the sample and buffer can bemixed, in which case, the first, second, and third chambers can bebuffer, sample collection, and mixing chambers, and the first and secondports can be buffer and sample ports. The sample and buffer can beequally mixed, in which case, r=1. To effect equal mixing of the sampleand buffer, S₁≅S₂ and 2A₁≅A₂, or alternatively, A₁≅A₂ and 2S₁≅S₂. Themixing chamber can include a dispense port, in which case, the preferredmethod can further moving a third plunger, such as buffered sampledispense plunger, towards the dispense port to dispense the fluidmixture from the mixing chamber out through the dispense port, e.g., bypushing it with the buffer dispense plunger. The buffered sampledispense plunger can also be moved within the mixing chamber against thebuffer port, e.g., by pushing it with the sample dispense plunger.

[0042] The buffer port may include a seal, in which case, the bufferedsample dispense plunger can include a stylus that breaks the seal whenthe buffered sample dispense plunger is seated against the buffer port.When the sample dispense plunger is mated with the buffered sampledispense plunger, it can be adjacent the sample port, allowing thesample to flow through the sample port immediately upon movement of thesample dispense plunger. The buffered sample dispense plunger caninclude a through port, in which case, the buffer can be dispensed fromthe buffer chamber into the mixing chamber via the through port. Thebuffered sample solution can be mixed within the mixing chamber simplythrough the dispensing process, or additionally by a mixing motor. Thepreferred method can be automated by mechanically coupling one or moredrive assemblies to the sample and buffer dispense plungers.

FLOW IMMUNOASSAY ASSEMBLY WITH ROTARY VALVE

[0043] The present inventions are also directed methods and assembliesfor selectively distributing and dispensing fluids using a rotary valvefor purposes such as performing immunoassay testing.

[0044] In accordance with a first aspect of the present invention, arotary valve comprises a stator and rotor disposed within the stator.The rotor is clockable between a dispense configuration, a firstauxiliary dispense configuration, and a second auxiliary dispenseconfiguration. When the rotor is clocked in the dispense configuration,it comprises a plurality of dispense channels connected between aplurality of entry dispense ports and a plurality of exit dispense portsdisposed in the stator. When the rotor is clocked in the first auxiliarydispense configuration, the rotor comprises a first plurality ofauxiliary dispense channels connected between a plurality of auxiliaryentry dispense ports disposed on the stator and the plurality of exitdispense ports. When the rotor is clocked in the second auxiliarydispense configuration, the rotor comprises a second plurality ofauxiliary dispense channels connected between the plurality of entrydispense ports and the plurality of exit dispense ports. In this manner,a fluid can be flowed through the rotary valve when the rotor is clockedin the dispense configuration, and another fluid can be flowed throughthe rotary valve when the rotor is clocked in either the first auxiliaryor the second auxiliary dispense configuration.

[0045] In a non-limiting preferred method, the dispense configurationcan be clocked substantially 90° from the first auxiliary dispenseconfiguration and substantially 0° from the second auxiliary dispenseconfiguration, i.e., the dispense configuration and second auxiliarydispense configuration are the same, so that a first and second fluidcan be flowed through the rotary valve without requiring rotation of therotor. The plurality of exit dispense ports can be clocked substantially180° from the plurality of entry dispense ports and substantially 90°from the plurality of auxiliary entry dispense ports. In this case, theplurality of dispense channels can comprise a plurality of throughchannels connecting the plurality of entry dispense ports and theplurality of exit dispense ports. The first plurality of auxiliarydispense channels can comprise a plurality of through channels connectedto the plurality of auxiliary entry dispense ports, and a plurality ofsubstantially 90° arcuate surface channels connected between theplurality of through channels and plurality of exit dispense ports. Thesecond plurality of auxiliary dispense channels can comprise a pluralityof substantially 90° arcuate surface channels connected between theplurality of auxiliary entry dispense ports and the plurality of exitdispense ports.

[0046] In accordance with a second aspect of the present inventions, arotary valve comprises a stator and a rotor disposed within the stator.The rotor is clockable in a distribution configuration, in which case,the rotor comprises a feed channel connecting a feed port to an entrydistribution port of a first distribution port pair disposed on thestator. The rotor further comprises a plurality of distribution channelsconnecting an exit distribution port of each previous distribution portpair to an entry distribution port of each next distribution port pair.In this manner, fluid can be distributed amongst several chambersthrough a single feed port.

[0047] In a non-limiting preferred embodiment, the feed port can beclocked substantially 90° from the first distribution port pair, inwhich case, the feed channel comprises a through channel connected tothe feed port, and a substantially 90° arcuate feed surface channelconnected between the through channel and the entry distribution port ofthe first distribution port pair. The distribution channels can be aplurality of longitudinal surface channels that connect a rectilinearpattern of distribution port pairs. The rotor can further include a ventchannel that connects an exit distribution port of the last distributionport pair with a vent port disposed on the stator. The vent port can beclocked substantially 180° from the last distribution port pair, inwhich case, the vent channel can comprise a first substantially 90°arcuate vent surface channel connected to the exit distribution port ofthe last distribution port pair, a second substantially 90° arcuate ventsurface channel connected to the vent port, and a through channelconnecting the first and second arcuate vent channels.

[0048] The rotor can further be clocked between the dispenseconfiguration, first auxiliary dispense configuration, and secondauxiliary configuration, as hereinbefore described. In this case, thedispense configuration may be clocked 90° from the distributionconfiguration, the first auxiliary dispense configuration and thedistribution configuration may be clocked substantially 0° from eachother, and the second auxiliary dispense configuration and dispenseconfiguration may be clocked substantially 0° from each other. Thus, thefirst auxiliary dispense configuration and the distributionconfiguration can be the same, so that a fluid can be distributedamongst several chambers and another fluid can be dispensed withoutrotating the rotor, and the second auxiliary dispense configuration anddispense configuration can be the same, so that the both fluids can bedispensed without rotating the rotor.

[0049] In accordance with a third aspect of the present inventions, aflow immunoassay assembly for testing a sample comprises a plurality ofsample distribution chambers, a plurality of buffer chambers, and aplurality of immunoassay reaction chambers. The flow immunoassayassembly further comprises a stator and a rotor disposed within thestator. That stator includes a plurality of entry dispense ports influid communication with the plurality of sample distribution chambers,a plurality of auxiliary entry dispense ports in fluid communicationwith the plurality of buffer chambers, and a plurality of exit dispenseports in fluid communication with the plurality of immunoassay reactionchambers. The rotor is clockable between a dispense configuration and afirst auxiliary dispense configuration.

[0050] When the rotor is clocked in the dispense configuration, itcomprises a plurality of dispense channels connected between a pluralityof entry dispense ports (and thus, the plurality of sample distributionchambers) and the plurality of exit dispense ports (and thus, theplurality of immunoassay reaction chambers). When the rotor is clockedin the first auxiliary dispense configuration, the rotor comprises afirst plurality of auxiliary dispense channels connected between theplurality of auxiliary entry dispense ports (and thus, the plurality ofbuffer chambers) and the plurality of exit dispense ports (and thus, theimmunoassay reaction chambers). In this manner, sample can be flowedfrom the plurality of sample distribution chambers, through the rotaryvalve, and into the plurality of immunoassay reaction chambers, when therotor is clocked in the dispense configuration, and buffer can be flowedfrom the plurality of buffer chambers, through the rotary valve, andinto the plurality of immunoassay reaction chambers, when the rotor isclocked in the first auxiliary dispense configuration.

[0051] In a non-limiting preferred embodiment, the rotor can be furtherclocked in a second auxiliary dispense configuration, in which case, therotor comprises a second plurality of auxiliary dispense channelsconnected between the plurality of auxiliary entry dispense ports (andthus, the plurality of buffer chambers) and the plurality of exitdispense ports (and thus, the immunoassay reaction chambers). Thedifferent configurations and ports and be clocked in relation to eachother in a manner similar to that hereinbefore described, so that abuffer flow can be performed, a sample flow can be performed afterclocking the rotor 90°, and then another buffer flow can be performedwithout clocking the rotor.

[0052] In accordance with a fourth aspect of the present inventions, amethod of controlling the flow of a sample within a flow immunoassayassembly having a rotary valve, comprises flowing buffer from aplurality of buffer chambers through the plurality of immunoassayreaction chambers while the rotary valve is in a first auxiliarydispense configuration, and flowing the sample from a plurality ofsample distribution chambers through the plurality of immunoassayreaction chambers while the rotary valve is in a dispense configuration.In a non-limiting preferred method, the dispense configuration comprisesa sample flow configuration, and the first auxiliary dispenseconfiguration comprises a buffer pre-wash configuration, in which case,the plurality of immunoassay reaction chambers is pre-washed with thebuffer while the rotary valve is in the buffer pre-wash configuration.The buffer can also be flowed from the plurality of buffer chambersthrough the plurality of immunoassay reaction chambers while the rotaryvalve is in a second auxiliary dispense configuration, e.g., a bufferpost-wash configuration.

[0053] In accordance with a fifth aspect of the present invention, aflow immunoassay assembly comprises a plurality of sample distributionchambers and a plurality of immunoassay reaction chambers. The flowimmunoassay assembly further comprises a stator and a rotor disposedwithin the stator. The stator comprises a feed port, and plurality ofdistribution port pairs in fluid communication with the plurality ofsample distribution chambers, with each of the distribution port pairscomprises an entry distribution port and an exit distribution port. Thestator further comprises a plurality of exit dispense ports in fluidcommunication with the plurality of immunoassay reaction chambers. Therotor is clockable in a distribution configuration, in which case, therotor comprises a feed channel connecting the feed port to an entrydistribution port of a first distribution port pair (and thus, the firstsample distribution chamber), and a plurality of distribution channelsconnecting an exit distribution port of each previous distribution portpair (and thus, the previous sample distribution chamber) to an entrydistribution port of each next distribution port pair (and thus, thenext sample distribution chambers).

[0054] In a non-limiting preferred embodiment, the stator may comprise avent port, and the rotor may comprise a vent channel connecting an exitdistribution port of the last distribution port pair (and thus, the lastsample distribution chambers). To provide for sample and buffer flows,the rotor can further be clocked between the dispense configuration,first auxiliary dispense configuration, and second auxiliaryconfiguration, as hereinbefore described. Also, the differentconfigurations and ports can be clocked in relation to each other in amanner similar to that hereinbefore described, so that the sample can bedistribution to the sample distribution chambers, the buffer can beflowed through the immunoassay reaction chambers, the sample can beflowed from the sample distribution chambers through the immunoassayreaction chambers after clocking the rotor 90°, and the buffer can beagain flowed from the buffer chambers through the immunoassay reactionchambers.

[0055] In accordance with an eighth aspect of the present inventions, amethod of controlling the flow of sample within a flow immunoassayassembly comprises placing a rotary valve in a distributionconfiguration, and flowing sample from a sample feed port into aplurality of sample distribution chambers while the rotary valve is inthe distribution configuration. In a non-limiting preferred method, thesample can be cascaded into the plurality of sample distributionchambers. Air can further be vented from the plurality of sampledistribution chambers via the rotary valve during the sampledistribution. The sample can also be prevented from flowing through aplurality of immunoassay reaction chambers when the rotary valve is inthe distribution configuration to prevent premature dispensing of thesample. The rotary valve can also be placed into dispense, firstauxiliary dispense, and second auxiliary dispense configuration, e.g.,sample dispense, buffer pre-wash, and buffer post-wash configurations,to effect the aforementioned sample and buffer flows through theplurality of immunoassay reaction chambers. The distribution and firstauxiliary dispense configurations can be clocked substantially 0° fromeach other, so that the sample distribution and buffer pre-wash can beperformed without rotating the rotor. Similarly, the dispense and secondauxiliary dispense configuration can be clocked substantially 0° fromeach, so that the sample dispense and buffer post-wash can be performedwithout rotating the rotor.

[0056] In accordance with a seventh aspect of the present inventions, aflow immunoassay assembly comprises a plurality of sample distributionchambers, a plurality of immunoassay reaction chambers, and a rotaryvalve clockable between a distribution configuration to place a samplefeed port in fluid communication with the plurality of sampledistribution chambers, and a dispense configuration to place theplurality of sample distribution chambers in fluid communication withthe plurality of immunoassay reaction chambers. In a non-limitingpreferred embodiment, the flow immunoassay assembly can further comprisea plurality of buffer chambers, in which case, the rotary valve can beclockable in a first auxiliary dispense configuration to place theplurality of buffer chambers into fluid communication with the pluralityof immunoassay reaction chambers, and a second auxiliary dispenseconfiguration to further place the plurality of buffer chambers intofluid communication with the plurality of immunoassay reaction chambers.The rotary valve can be clocked in the distribution configuration tofurther prevent fluid communication between the plurality ofdistribution chambers and the plurality of immunoassay reactionchambers, and in the dispense configuration to further prevent fluidcommunication between the sample feed ort and the plurality of sampledistribution chambers.

[0057] In accordance with an eighth aspect of the present inventions, aflow immunoassay assembly comprises a plurality of sample distributionchambers, a plurality of buffer chambers, a plurality of immunoassayreaction chambers, and a rotary valve clockable between a dispenseconfiguration to place the plurality of sample distribution chambersinto fluid communication with the plurality of immunoassay reactionchambers, and a different first auxiliary dispense configuration toplace the plurality of buffer chambers into fluid communication with theplurality of immunoassay reaction chambers. In a non-limiting preferredembodiment, the rotary valve can be placed into a second auxiliarydispense configuration to further place the plurality of buffer chambersin fluid communication with the plurality of immunoassay reactionchambers.

METHOD OF MANUFACTURING A SELF-SEALING CHAMBER

[0058] The present inventions are also directed to methods formanufacturing self sealing chambers by interference fitting barrierswithin the chambers.

[0059] In accordance with a first aspect of the present inventions, amethod of substantially sealing a chamber, comprises providing a dieplate through which a channel extends and a compression plate throughwhich a tapered channel extends. The tapered channel includes a firstopening and a second opening opposite the first opening. The secondopening is equal to or smaller than the chamber opening. The methodfurther comprises providing a chamber adapter that has a female portionand a passage extending therethrough The method further comprises matingthe chamber adapter female portion with a compression plate maleportion, and associating the chamber with the chamber adapter passage,e.g., by disposing the chamber within the chamber adapter passage. Themethod further comprises disposing a compressible material on the dieplate and forming the barrier by pushing a pin through the compressiblematerial into the die plate passage. The method further comprisespushing the barrier into the first tapered channel opening, through thetapered channel and into the chamber adapter passage via the secondtapered channel opening. Lastly, the method further comprises pushingthe barrier through the chamber adapter passage into the chamberopening.

[0060] In a non-limiting preferred method, the barrier is pushed throughthe compression plate tapered channel and chamber adapter passage usingthe pin. The passages through which the barrier passes are preferablygeometrically similar, e.g., circular. In the preferred method, thebarrier can be composed of a porous material, suitable for constructingan immunoassay reaction chamber. These steps can be repeated to disposeanother barrier within an opening located at the other end of thechamber.

[0061] In accordance with a second aspect of the present inventions, amethod of substantially sealing a chamber comprises providing a barrierhaving an uncompressed size larger than an opening at one of thechamber. The method further comprises providing a tool through which atapered passage extends. The tapered passage includes a first openingand a second opening opposite the first opening. The second opening isequal to or smaller than the chamber opening. The method furthercomprises associating the chamber opening with the second taperedpassage opening, introducing the barrier into the first tapered passageopening, and passing the barrier through the tapered passage, and intothe chamber opening via the second tapered passage opening. In thismanner, a barrier within an uncompressed diameter greater than thechamber opening can be placed therein and allowed to expand into acompression fit with the chamber. In a non-limiting preferred method,the afore-described details can be incorporated therein.

[0062] In accordance with a third aspect of the present inventions, amethod of manufacturing an immunoassay reaction chamber comprisesproviding a hollow column with a channel, interference fitting a firstporous frit within the column channel, disposing reagent within thecolumn channel, and interference fitting a second porous frit within thecolumn channel, wherein the reagent is contained between the first andsecond frits. In a non-limiting preferred method, each of the frits hasan uncompressed size that is larger than the column channel, and eachfrit is interference fit within the column channel by disposing the fritwithin the column channel in a compressed stated, and allowing the fritto expand to generate a compressive force between it and the columnchannel. Preferably, the compressive force generated by the frit and thecolumn channel is sufficient to hold the frit in place when fluid isflowed through the column channel. Each frit can be disposed within thecolumn in a compressed state by associating the column channel with atapered passage having a first opening and a second opening equal to orsmaller than the column channel. The frit can then be pushed into thefirst tapered passage opening, through the tapered passage and into thecolumn channel via the second tapered passage opening. The columnchannel can be cylindrical, in which case, the first and second fritswill be circular.

[0063] In accordance with a fourth aspect of the present inventions, animmunoassay reaction chamber comprises a hollow column with a channel, afirst and second porous frits interference fit within the columnchannel, and reagent contained within the column channel between thefirst and second frits. In a non-limiting preferred embodiment, each ofthe frits has an uncompressed size larger than the column channel, inwhich case, each frit can be interference fit within the column channelby a compressive force between each frit and the column channel. Thecolumn channel can be cylindrical, in which case, the first and secondfrits will be circular.

ROTARY VALVE WITH COMPLIANT LINING

[0064] The present inventions are also directed to rotary valves thatprovide a rotor with a compliant lining.

[0065] In accordance with a first aspect of the present inventions, arotary valve comprises a rigid hollow stator and a rotor disposed withinthe stator. The rotor comprises a rigid core and a compliant lininginjection molded onto the rigid core, wherein the compliant lining issealingly engaged with an inner bearing surface of the stator andcomprises one or more surface channels that can be placed into fluidcommunication with one or more ports disposed on the stator. In anon-limiting preferred embodiment, the rigid core is composed ofpolycarbonate and the compliant lining is composed of polyurethane. Thesurface channels can be, e.g., arcuate or longitudinal surface channels.The rigid core can comprise one or more through channels, in which case,the one or more surface channels can intersect the one or more throughchannels to form a continuous channel.

[0066] In accordance with a second aspect of the present inventions, arotor for a rotary valve comprises a rigid core and a compliant lininginjection molded onto the rigid core, wherein the compliant liningcomprises one or more surface channels. In a non-limiting preferredembodiment, the previously mentioned detailed features can beincorporated into the rotor.

[0067] In accordance with a third aspect of the present inventions, arotary valve comprises a rigid hollow stator and a rotor disposed withinthe stator. The rotor comprises a rigid core including a ridge and acompliant lining injection molded onto the ridge to form a surfacechannel. The compliant lining is sealingly engaged with an inner bearingsurface of the stator, and the surface channel can be placed into fluidcommunication with the flow port.

[0068] In a non-limiting preferred embodiment, the rigid core cancomprise a plurality of equidistant arcuate ridges, in which case, thecompliant lining can be injection molded onto the plurality of arcuateridges to form a plurality of arcuate surface channels that can beplaced into fluid communication with a plurality of flow ports disposedon the stator. The rigid core can also comprise a longitudinal ridgethat intersects the plurality of arcuate ridges, in which case, thecompliant lining can be injection molded onto the longitudinal ridge toform a longitudinal surface channel that can be placed into fluidcommunication with another flow port disposed on the stator, or even aplurality of longitudinal surface channels that can be placed into fluidcommunication with another plurality of flow ports disposed on thestator.

[0069] Each ridge can have a pair of opposing lateral surfaces and anadjacent circumferential surface. The compliant lining can be injectionmolded onto the opposing lateral surfaces of the ridge, while leavingthe circumferential surface of the ridge exposed, to form the surfacechannel. The compliant lining can also have a surface channel stop, inwhich case, the ridge has another pair of opposing lateral surfaces andanother adjacent circumferential surface. The compliant lining can becan be injection molded onto the other opposing lateral surface and theother adjacent circumferential surface of the ride to form the surfacechannel stop.

[0070] In accordance with a fourth aspect of the present inventions, arotor for rotary valve comprises a rigid core including a ridge, and acompliant lining injection molded onto the ridge to form a surfacechannels. In a non-limiting preferred embodiment, the previouslymentioned detailed features can be incorporated into the rotor.

FLOW IMMUNOASSAY ASSEMBLY WITH MULTIPLE FLOW CHANNELS

[0071] The present inventions are also directed to methods andassemblies for flowing a single sample through a plurality ofimmunoassay reaction chambers.

[0072] In accordance with a first aspect of the present inventions, aflow immunoassay assembly for testing a single sample, comprises asample feed port, a plurality of immunoassay reaction chambers forperforming a plurality of different assays on the sample, a plurality ofsample flow channels in fluid communication between the sample feed portand the plurality of immunoassay reaction chambers, and one or moresample drive assemblies configured to pump the sample through theplurality of sample flow channels into the plurality of immunoassayreaction chambers. In this manner, several immunoassay tests can besimultaneously performed on the sample.

[0073] In a non-limiting preferred embodiment, the flow immunoassayassembly can further comprise a plurality of buffer flow channels influid communication with the plurality of immunoassay reaction chambers,and one or more buffer drive assemblies configured to pump the bufferthrough the plurality of buffer flow channels into the plurality ofimmunoassay reaction chambers. The preferred flow immunoassay assemblycan further comprise a plurality of sample distribution chambersconfigured to receive the sample from the sample feed port, and aplurality of buffer chambers containing the buffer. The preferred flowimmunoassay assembly can further comprise a plurality of sample dispenseplungers disposed within the plurality of sample distribution chambers,and a plurality of buffer dispense plungers disposed within theplurality of buffer chambers, in which case, the one or more sampledrive assemblies can have a plurality of sample dispense plunger driversthat are configured to move the plurality of sample dispense plungerswithin the plurality of sample distribution chambers to pump the sample,and the one or more buffer drive assemblies can have a plurality ofbuffer dispense plunger drivers that are configured to move theplurality of buffer dispense plungers within the plurality of bufferchambers to pump the buffer.

[0074] A valve, such as a rotary valve, can be used to selectively placethe sample feed port in fluid communication with the plurality of sampledistribution chambers, for selectively placing the plurality ofdistribution chambers in fluid communication with the plurality ofimmunoassay reaction chambers, and for selectively placing the pluralityof buffer chambers in fluid communication with the plurality ofimmunoassay reaction chambers. The number of sample flow channels andbuffer flow channels can be, e.g. five or more.

[0075] In accordance with a second aspect of the present inventions, amethod of analyzing a single sample comprises pumping sample from asample feed port into a plurality of sample distribution chambers, andpumping the sample from the sample distribution chambers through aplurality of immunoassay reaction chambers for performing a plurality ofdifferent assays on the sample, and measuring a reaction occurring inthe plurality of immunoassay reaction chambers. In a non-limitingpreferred method, a plurality of analyte detectable sample solutions areproduced within the plurality of immunoassay reaction chambers, in whichcase, the reactions can be measured by flowing the plurality of analytedetectable sample solutions through a plurality of read cells, andmeasuring a plurality of analyte indicators, e.g., different labeledantigen, in the plurality of analyte detectable sample solutions. Thepreferred method further comprises pumping buffer from a plurality ofbuffer chambers through the plurality of immunoassay reaction chambers.

[0076] In accordance with a third aspect of the present inventions, aflow immunoassay assembly for testing a single sample, comprises asample feed port, a first plurality of immunoassay reaction chambers, afirst plurality of sample flow channels in fluid communication with thefirst plurality of reaction chambers, and a first sample drive assemblyconfigured to pump the sample through the first plurality of sample flowchannels into the first plurality of immunoassay reaction chambers. Theflow immunoassay assembly further comprises a second plurality ofimmunoassay reaction chambers, a second plurality of sample flowchannels in fluid communication with the second plurality of reactionchambers, and a second sample drive assembly configured to pump thesample through the second plurality of sample flow channels into thesecond plurality of immunoassay reaction chambers. In this manner, thesample flow rate and volume can be independently controlled through thefirst and second pluralities of sample flow channels.

[0077] In a non-limiting preferred embodiment, the flow immunoassayassembly can further include a first plurality of buffer flow channelsin fluid communication with the first plurality of reaction chambers,and a first buffer drive assembly configured to pump the buffer throughthe first plurality of buffer flow channels into the first plurality ofimmunoassay reaction chambers. The preferred flow immunoassay assemblycan further include a second plurality of buffer flow channels in fluidcommunication with the second plurality of reaction chambers, and asecond buffer drive assembly configured to pump the buffer through thesecond plurality of buffer flow channels into the second plurality ofimmunoassay reaction chambers. In this manner, the buffer flow rate andvolume can be independently controlled through the first and secondpluralities of buffer flow channels. The preferred flow immunoassayassembly can further include many of the other features described above,such sample distribution chambers, buffer chambers, read cells, sampledispense plungers, sample dispense plunger drivers, buffer dispenseplungers, and buffer dispense plunger drivers.

[0078] In accordance with a fourth aspect of the present inventions, amethod of analyzing a sample comprises pumping sample through a firstplurality of immunoassay reaction chambers using a first sample driveassembly, pumping the sample through a second plurality of immunoassayreaction chambers using a second sample drive assembly, and measuring areaction within each of the first and second pluralities of immunoassayreaction chambers.

[0079] In a non-limiting preferred method, a first plurality of analytedetectable sample solutions can be produced within the first pluralityof immunoassay reaction chambers, and a second plurality of resultsolutions can be produced within the second plurality of immunoassayreaction chambers, in which case, the reactions can be measured byflowing the first and second pluralities of analyte detectable samplesolutions through first and second pluralities of read cells, andmeasuring first and second pluralities of analyte indicators, e.g.,different labeled antigen, in the first and second pluralities ofanalyte detectable sample solutions. The sample can be pumped throughthe first and second pluralities of immunoassay reaction chambers atsubstantially different rates and/or different quantities. The preferredmethod may further comprise pumping buffer through the first pluralityof immunoassay reaction chambers using a first buffer drive assembly,and pumping buffer through the second plurality of immunoassay reactionchambers using a second buffer drive assembly.

IMMUNOASSAY CHEMISTRY CASSETTE BARCODE FOR SYSTEM CUSTOMIZATION

[0080] The present inventions are also directed to assemblies, systems,and methods for using a chemistry cassette barcode to obtain informationassociated with the cassette.

[0081] In accordance with a first aspect of the present inventions, abarcode assembly for use with an analyte testing system comprises abarcode affixed to the chemistry cassette, and the barcode assemblyfurther comprises a barcode reader mounted within a test console of ananalyte testing system. The barcode comprises information associatedwith the chemistry cassette, and the barcode reader is configured forscanning the barcode when the chemistry cassette is received within thetest console. In the non-limiting preferred embodiment, the barcodeinformation can indicate a test panel contained within the chemistrycassette, e.g., the NIDA drugs-of-abuse test panel, a date ofmanufacture of the chemistry cassette, test calibration information,and/or information indicating whether the chemistry cassette has beenpreviously used, e.g., a checksum code.

[0082] In accordance with a second aspect of the present inventions, amethod of obtaining information within an analyte testing systemcomprises receiving a chemistry cassette within a test console, andscanning a barcode containing information associated with the chemistrycassette. In the non-limiting preferred method, the barcode informationcan indicate the previously described parameters of the system. Thepreferred method may further comprise preventing the chemistry cassettefrom being used within the test console if the barcode informationindicates that the chemistry cassette has been previously used.

[0083] In accordance with a third aspect of the present inventions, aself-customizing analyte testing system comprises a test console, achemistry cassette receivable within the test console, a barcode affixedto the chemistry cassette, a barcode reader configured for scanning thebarcode, and circuitry electrically coupled to the barcode reader formodifying one or more operational parameters of the testing system basedon information contained in the barcode.

[0084] In a non-limiting preferred embodiment, the barcode reader andcircuitry, which can be a CPU, can be contained in the test console, andthe barcode reader can be configured to scan the barcode while thechemistry cassette is received within the test console. The circuitrycan be configured to modify one or more testing parameters for eachanalyte of a multi-analyte test panel. For example, if the barcodeinformation comprises test calibration information, the circuitry can beconfigured to calibrate the test panel using the test calibrationinformation. If the testing system comprises a flow immunoassayassembly, the circuitry can be configured to modify each of theplurality of flow channels, e.g., by modifying the flow volume or flowrate.

[0085] In accordance with a fourth aspect of the present inventions, amethod of customizing an analyte testing system comprises receiving achemistry cassette within a test console, scanning a barcode containinginformation associated with the chemistry cassette, and modifying one ormore operational parameters based on the barcode information. In anon-limiting preferred method, the testing system can be customized bymodifying one or more testing parameters for each analyte of amulti-analyte test panel as previously described. For example, a testpanel can be calibrating using test calibration information obtainedfrom the barcode, or a plurality of flow channels within a flowimmunoassay assembly can be modified.

[0086] In accordance with a fifth aspect of the present inventions, aself-customizing multi-analyte flow immunoassay testing system comprisesa flow immunoassay assembly, a barcode comprising information associatedwith the flow immunoassay assembly, a barcode reader configured forscanning the barcode, and control circuitry electrically coupled to thebarcode reader. The flow immunoassay assembly comprises a plurality offlow channels corresponding to a plurality of analytes to be tested, andthe control circuitry is configured to modify one or more flow channelparameters for each of the plurality of flow channels, based on thebarcode information. In the non-limiting preferred embodiment, thecontrol circuitry comprises a CPU that is configured for modifying theflow rate and/or volume of the flow channels.

[0087] In accordance with a sixth aspect of the present inventions, amethod of customizing a multi-analyte flow immunoassay testing systemcomprises scanning a barcode comprising information associated with theflow immunoassay assembly, and modifying one or more flow channelparameters for each of a plurality of flow channels based on the barcodeinformation. In a non-limiting preferred method, the flow rate and/orflow volume of the flow channels are modified.

DRUG AND ALCOHOL ASSAY ASSEMBLY

[0088] The present inventions are also directed to assemblies andmethods for performing an assay on a sample for drugs and alcohol.

[0089] In accordance with a first aspect of the present inventions, adrug and alcohol assay assembly comprises a sample feed port, andimmunoassay reaction chamber containing a drug reagent, and a firstsample flow channel in fluid communication between the sample feed portand the immunoassay reaction chamber. The assembly further comprises analcohol reaction chamber configured for containing an alcohol reagent,and a second sample flow channel in fluid communication between thesample feed port and the alcohol reaction chamber.

[0090] In a non-limiting preferred embodiment, the assembly can furthercomprise a first buffer flow channel in fluid communication with theimmunoassay reaction chamber, a second buffer flow channel in fluidcommunication with the alcohol reaction chamber, and a reagent chamberdisposed within the buffer flow channel. The reagent chamber can containdry alcohol reagent. In this case, the alcohol reagent can comprise areagent solution, where the reagent chamber is configured to produce thereagent solution for dispensing in the alcohol reaction chamber whenbuffer flows through the buffer flow channel. The drug reagent can bespecific to one of the NIDA drugs-of-abuse.

[0091] In accordance with a second aspect of the present inventions, adrug and alcohol assay assembly comprises an immunoassay reactionchamber containing a drug reagent, a first sample chamber in fluidcommunication with the immunoassay reaction chamber, and beingconfigured for containing sample, an alcohol reaction chamber configuredfor containing an alcohol reagent, and a second sample chamber in fluidcommunication with the immunoassay reaction chamber, and beingconfigured for containing the sample.

[0092] In a non-limiting preferred embodiment, the assembly can furthercomprises a sample feed port in fluid communication with the first andsecond sample chamber. The preferred assembly can further comprise asample dispense plunger disposed within the first sample chamber, andcan be movable to dispense the sample from the first sample chamber intothe immunoassay reaction chamber. The preferred assembly can furthercomprise an air flow port in communication with the second samplechamber, and can be configured to dispense the sample from the secondsample chamber into the alcohol reaction chamber when air is flowedthrough the air flow port. The preferred assembly can further comprise avalve for selectively placing the first sample chamber in fluidcommunication with the immunoassay reaction chamber, and for selectivelyplacing the second sample chamber in fluid communication with thealcohol reaction chamber. The valve can be a rotary valve, in whichcase, it can include a stator and a rotor disposed within the stator,wherein the second sample chamber comprises a shear valve formed withinthe rotor.

[0093] The preferred assembly can further comprise a first bufferchamber that contains buffer and is in fluid communication with theimmunoassay reaction chamber, a second buffer chamber, and a reagentchamber in fluid communication between the second buffer chamber and thealcohol reaction chamber. In this case, the preferred assembly canfurther comprise a first buffer dispense plunger movable within thefirst buffer chamber to dispense buffer from the first buffer chamberinto the immunoassay reaction chamber to hydrate dry drug reagenttherein. The preferred assembly can further comprise a second a secondbuffer dispense plunger movable within the second buffer chamber todispense the buffer from the second buffer chamber through theimmunoassay reaction chamber to hydrate dry alcohol reagent therein,wherein a reagent solution is produced and dispensed into the alcoholreaction chamber.

[0094] In accordance with a third aspect of the present inventions, amethod of performing a drug and alcohol assay, comprises flowing sampleinto an immunoassay reaction chamber containing a drug reagent, reactingthe sample and the drug reagent, flowing the sample into an alcoholreaction chamber containing an alcohol reagent, and reacting the sampleand the alcohol reagent.

[0095] In a non-limiting preferred method, the method can furthercomprise flowing a first buffer into the immunoassay reaction chamber toproduce a hydrated drug reagent, flowing a second buffer through areagent chamber to produce an alcohol reagent solution, and flowing thealcohol reagent solution into the alcohol reaction chamber. The sampleand first buffer can be pumped into the immunoassay reaction chamber,and the sample and second buffer can be pumped into the alcohol reactionchamber.

[0096] In accordance with a fourth aspect of the present inventions, aflow immunoassay and alcohol detection assembly comprises an immunoassayreaction chamber containing a drug reagent, a first sample chamber influid communication with the immunoassay reaction chamber, a read cellin fluid communication with the immunoassay reaction chamber, a firstenergy source configured to transmit energy through the read cell, and afirst energy detector configured to receive energy from the read cell.The assembly further comprises an alcohol reaction chamber configuredfor containing an alcohol reagent, a second sample chamber in fluidcommunication between the sample feed port and the immunoassay reactionchamber, a second energy source configured to transmit energy throughthe alcohol reaction chamber, and a second energy detector configured toreceive energy from the alcohol reaction chamber. The assembly alsocomprises processing circuitry configured for determining a presence ofa drug in the sample based on the energy received by the first energydetector, and configured for determining a presence of alcohol in thesample based on the energy received by the second energy detector.

[0097] In a non-limiting preferred embodiment, the afore-describedfeatures can be incorporated into the assembly. The preferred assemblycan further comprise a calibrator chamber in fluid communication withthe alcohol reaction chamber, and a calibrator dispense plunger movablewithin the calibrator chamber dispense calibrator solution having apredetermined quantity of alcohol from the calibrator chamber into thealcohol reaction chamber to react with the reagent solution. The firstand second energy sources can be optical sources, and the first andsecond energy detectors can be optical detectors.

[0098] In accordance with a fifth aspect of the present inventions, amethod of analyzing a sample comprises flowing the sample through animmunoassay reaction chamber, wherein the immunoassay reaction chamberproduces a drug detectable sample solution containing a drug indicator,measuring the drug indicator, and determining a presence of a druganalyte within the sample based on the measured drug indicator. Themethod further comprises flowing the sample into an alcohol reactionchamber containing an alcohol reagent, wherein the alcohol reactionchamber produces an alcohol detectable sample solution containing analcohol indicator, measuring the alcohol indicator, and determining apresence of alcohol within the sample based on the measured alcoholindicator.

[0099] In a non-limiting preferred method, the drug indicator can emitoptical energy when excited, and the alcohol indicator measuringcomprises optically exciting the displaced labeled antigen to emitoptical energy and measuring the emitted optical energy. The alcoholindicator can exhibit an optical absorbance value at a specific opticalwavelength, wherein the alcohol indicator measuring comprisestransmitting optical energy through the alcohol detectable samplesolution at the specified wavelength, and measuring the transmittedoptical energy after it is transmitted through the alcohol detectablesample solution. The preferred method can further comprise flowing afirst buffer into the immunoassay reaction chamber to produce a hydrateddrug reagent, wherein the sample reacts with the hydrated drug reagentto produce the drug detectable sample solution, flowing a second bufferthrough a reagent chamber to produce an alcohol reagent solution, andflowing the alcohol reagent solution into the alcohol reaction chamber,wherein the sample reacts with the alcohol reagent solution to producethe alcohol detectable sample solution. The method can furthercomprising flowing a calibrator solution containing a predeterminedquantity of alcohol into said alcohol reaction chamber to produce analcohol detectable calibration solution containing an initial alcoholindicator, measuring the initial alcohol indicator, and calibrating thealcohol detectable sample solution.

FLOW IMMUNOASSAY SCANNING ASSEMBLY

[0100] The present inventions are also directed to methods andassemblies for scanning a flow immunoassay assembly.

[0101] In accordance with a first aspect of the present inventions, aflow immunoassay scanning assembly comprises a plurality of immunoassayreaction chambers, a plurality of read cells in fluid communication withthe plurality of immunoassay reaction chambers, a detector having asensing beam, and a scanning drive assembly configured to translate thedetector to intersect the plurality of read cells with the sensing beam.In a non-limiting preferred embodiment, the detector comprises anoptical detector, and each of the immunoassay reaction chambers containsfluorescent labeled antigen that is displaced when an analog to thefluorescent labeled antigen flows through the immunoassay reactionchamber. Thus, the fluorescent labeled antigen can be detected by theoptical detector when flowed through the corresponding read cell. Thedetector can also be configured, such that the sensing beam intersectsthe plurality of read cells at an angle substantially perpendicular tothe longitudinal axes of the read cells. The scanning drive assembly canbe configured to translate the detector to repeatedly intersect theplurality of read cells with the sensing beam.

[0102] In accordance with a second aspect of the present inventions, amethod of testing the presence of a plurality of target analytes in asample comprises producing a plurality of immunoassay flow pathscontaining the sample, wherein an analyte indicator is produced in eachof the plurality of immunoassay flow paths in the presence of acorresponding target analyte. The method further comprises detecting anyof the plurality of analyte indicators in the plurality of immunoassayflow paths by scanning a sensing beam across the plurality ofimmunoassay flow paths.

[0103] In a non-limiting preferred method, the sensing beam comprises anoptical sensing beam, and the analyte indicator comprises a fluorescentlabeled antigen. The sensing beam can be scanned substantiallyperpendicular to the direction of the flow paths and repeatedly acrossthe plurality of flow paths. The preferred method can further compriseoutputting a plurality of signals based on the detection of any analyteindicators within the plurality of immunoassay flow paths, andprocessing the output signals to detect the present of the plurality oftarget analytes within the sample. The preferred method can furthercomprise detecting a location of each of the plurality of read cells, inwhich case, the detected analyte indicator is only processed when alocation of a corresponding one of the plurality of read cells isdetected.

[0104] In accordance with a third aspect of the present inventions, aflow immunoassay scanning assembly comprises a plurality of immunoassayreaction chambers, a plurality of read cells in fluid communication withthe plurality of immunoassay reaction chambers, and a detector having asensing beam. The flow immunoassay scanning assembly further comprises ascan head mechanism to which the detector and transmitter are mounted,and a scanning drive assembly configured to translate the detector andthe transmitter to intersect the plurality of read cells with thesensing beam and energy beam.

[0105] In a non-limiting preferred embodiment, the detector can be anoptical detector, and the transmitter can be an optical source, e.g., alaser, in which case, the analyte indicator can comprise fluorescentlabeled antigen that is exited by the laser beam into fluorescence. Thedetector may be configured, such that the sensing beam intersects theplurality of read cells at an angle substantially perpendicular to thelongitudinal axes of the read cells, and the transmitter is configured,such that the laser beam travels through the read cells at an anglesubstantially parallel to the longitudinal axes of the read cells. Thescanning drive assembly can be configured to translate the detector andtransmitter to repeatedly intersect the plurality of read cells with thesensing beam and energy beam. The preferred embodiment may also comprisea read cell detector fixably coupled to the scan head mechanism andconfigured to sense a location of each of the plurality of read cells,and processing circuitry for processing an output of the detector onlywhen the read cell detector senses the location of each of the pluralityof read cells. To facilitate detection of the read cells, read cellindicators, e.g., notches, can be spaced a distance equal to thedistance in which the read cells are spaced. The scanning drive assemblycan further comprise a rail that extends along the plurality of readcells, and a runner on which the scan head mechanism is fixably coupled.

[0106] In accordance with a fourth aspect of the present inventions, amethod of detecting the presence of a plurality of target analytes in asample comprises producing a plurality of immunoassay flow pathscontaining the sample, wherein an analyte indicator is produced in eachof the plurality of immunoassay flow paths in the presence of acorresponding target analyte, exciting the plurality of analyteindicators by scanning an energy beam across the plurality ofimmunoassay flow paths, and detecting any of the plurality of excitedanalyte indicators in the plurality of immunoassay flow paths byscanning a sensing beam across the plurality of immunoassay flow paths.In a non-limiting preferred method, the sensing beam can comprise anoptical sensing beam, and the energy beam can comprise an optical energybeam, such as a laser beam. The preferred method can further includescanning the sensing beam substantially perpendicular to the directionof the flow paths, and the energy beam scanned substantially parallel tothe direction of the flow paths. The preferred method can furtherinclude scanning the sensing and energy beams simultaneously andrepeatedly across the plurality of immunoassay flow paths.

ORTHOGONAL READ ASSEMBLY

[0107] The present inventions are also directed to methods andassemblies for transmitting and detecting energy within a read cell.

[0108] In accordance with a first aspect of the present inventions, anorthogonal read assembly comprises an immunoassay reaction chamber, aread cell having a lumen in fluid communication with the immunoassayreaction chamber, a transmitter configured to transmit energy throughthe lumen, and a detector configured to sense energy emittedtransversely from the lumen. In a non-limiting preferred embodiment, thetransmitter can comprise an optical transmitter, such as a laser, andthe detector can comprise an optical detector, e.g., a silicon diode.The optical transmitter can transmit optical energy at an oblique entryangle to the lumen, e.g., 45°, and the optical energy can be sensed bythe optical detector at an angle substantially perpendicular to thelumen. The read cell can be composed of a transparent plastic and can beparallel-pipe shaped. The lumen can be cylindrically shaped and mayinclude an optical transmission port, in which case, the opticaltransmitter can be configured to transmit the optical energy through thelumen via the optical transmission port.

[0109] In accordance with a second aspect of the present inventions, anorthogonal read assembly comprises an immunoassay reaction chambercontaining labeled antigen that is displaced when an analog to thelabeled antigen flows through the immunoassay reaction chamber, a readcell comprising a lumen in fluid communication with the immunoassayreaction chamber, a transmitter configured to transmit energy throughthe lumen to excite the labeled antigen to transversely emit energy fromthe lumen, and a detector configured to sense the transversely emittedenergy from the labeled antigen. In a non-limiting preferred embodiment,any of the afore-described detail features can be incorporated into theorthogonal read assembly.

[0110] In accordance with a third aspect of the present inventions, amethod of sensing an analyte within a sample comprises flowing thesample through an immunoassay reaction chamber to displace labeledantigen from the immunoassay reaction chamber, flowing displaced labeledantigen through a lumen of a read cell, transmitting energy along thelumen to excite the labeled antigen into transversely emitting energyfrom the lumen, and sensing the transversely emitted energy. In anon-limiting preferred method, any of the afore-described detailedfeatures can be incorporated into the steps of the method.

INTEGRAL SAMPLE COLLECTION TIP

[0111] The present inventions are also directed to assemblies forcollecting a sample from a mouth using an integrated sample collectiontip.

[0112] In accordance with a first aspect of the present inventions, asample collection assembly comprises a sample collection body configuredfor being placed within the mouth, wherein the sample collection bodycomprises a bore and one or more pores. The sample collection assemblyfurther comprises a conduit that disposed within the bore of the samplecollection body and that is in fluid communication with the one or morepores. In a non-limiting preferred embodiment, the conduit is bondedwithin the bore. The sample collection assembly can further include ahand piece that has a tip on which the sample collection body ismounted, and through which the conduit can extend. For example, the rearsurface of the sample collection body can be bonded to the front surfaceof the sample collection tip. The one or more pores can comprise aplurality of micropores. The sample collection body can be hydrophobic,and a hydrophilic surfactant can be disposed on the outer surface of thesample collection body.

[0113] In accordance with a second aspect of the present inventions, asample collection assembly comprises a sample collection body configuredfor being placed within the mouth, wherein the sample collection bodycomprises a bore and one or more pores. The sample collection assemblyfurther comprises a conduit that bonded within the bore of the samplecollection body and that is in fluid communication with the one or morepores. The adhesive force between the conduit and the bore is greaterthan the cohesive force of the sample collection body. In a non-limitingpreferred embodiment, the sample collection assembly can further includea hand piece that has a tip on which the sample collection body ismounted, and through which the conduit can extend. For example, the rearsurface of the sample collection body can be bonded to the front surfaceof the sample collection tip. The adhesive force between the rearsurface of the sample collection body and the front surface of the handpiece tip can be greater than the cohesive force of the samplecollection body. The one or more pores can comprise a plurality ofmicropores. The sample collection body can be hydrophobic, and ahydrophilic surfactant can be disposed on the outer surface of thesample collection body.

[0114] In accordance with a third aspect of the present invention, asample collection assembly comprises a sample collection body configuredfor being placed within the mouth, a sample collection chamber, aconduit in fluid communication with between the sample collection bodyand the sample collection chamber, and a pump configured to pump samplefrom the sample collection body, through the conduit, and into thesample collection chamber. The sample collection body comprises a boreand one or more pores, and the conduit is bonded within the bore of thesample collection body in fluid communication with the one or morepores. The adhesive force between the conduit and the bore is greaterthan the cohesive force of the sample collection body. In a non-limitingpreferred embodiment, the afore-described features can be incorporatedinto the sample collection assembly.

ALCOHOL DETECTION ASSEMBLY

[0115] The present inventions are also directed to assemblies andmethods for detecting alcohol using a reconstituted reagent solution.

[0116] In accordance with a first aspect of the present inventions, analcohol reaction assembly comprises an alcohol reaction chamber, areagent chamber in fluid communication with the alcohol reactionchamber, and a buffer chamber in fluid communication with the reagentchamber. The alcohol reaction assembly further includes a bufferdispense plunger disposed within the buffer chamber for dispensingbuffer from the buffer chamber, through the reagent chamber, and intothe alcohol reaction chamber, where it hydrates dry reagent therein toproduce a reagent solution. The alcohol reaction assembly furtherincludes a calibrator chamber in fluid communication with the alcoholreaction chamber, and a calibrator dispense plunger disposed within thecalibrator chamber to dispense a predetermined quantity of alcohol intothe alcohol reaction chamber. The alcohol reaction assembly alsoincludes a sample chamber in fluid communication with the alcoholreaction chamber, and being configured for containing a sample.

[0117] In a non-limiting preferred embodiment, the alcohol reactionassembly comprises buffer and calibrator drive assemblies can bemechanically coupled to the buffer and calibrator dispense plungers toautomate them. The components of the alcohol reaction assembly can alsobe arranged in a cassette and test console. For example, the chambersand plungers can be contained with the cassette, whereas the driveassemblies can be contained within the test console. In this case, thebuffer drive assembly can include a cassette loading drive assembly thatis configured to load the cassette into the test console, and a bufferdriver that is fixed within the test console and is configured to movethe buffer dispense plunger within the buffer chamber as the cassette isbeing loaded into the test console. The alcohol reaction assembly canfurther include an air blower and air flow port in communication withthe sample chamber to dispense the sample into the alcohol reactionchamber when air is pumped through the air flow port from the airblower. The alcohol reaction assembly can further include a vent port(which may be the same as the air flow port) in communication with thealcohol reaction chamber to vent air from the alcohol reaction chamberwhen the reagent solution and the calibrator solution are dispensedwithin the alcohol reaction chamber. The alcohol reaction assembly mayfurther include a mixing drive assembly that is magnetically coupled toa ferrous element within the alcohol reaction chamber to ensurereactions proceed to completion within the alcohol reaction chamber.

[0118] In accordance with a second aspect of the present inventions, analcohol reaction assembly comprises an alcohol reaction chamber, areagent chamber in fluid communication with the alcohol reactionchamber, and a buffer chamber in fluid communication with the reagentchamber. The alcohol reaction assembly further includes a bufferdispense plunger disposed within the buffer chamber for dispensingbuffer from the buffer chamber, through the reagent chamber, and intothe alcohol reaction chamber, where it hydrates dry reagent therein toproduce a reagent solution.

[0119] In a non-limiting preferred embodiment, the dry reaction in thereaction chamber comprises lyophilized alcohol dehydrogenase (ADH) andnicotinamide adenine dinucleotide (NAD). The buffer chamber can alsoinclude a seal that seals the buffer from the reagent chamber, in whichcase, the buffer dispense plunger can include a stylus that isconfigured to puncture the seal when the buffer dispense plunger ismoved toward the seal. The previously described features can also beincorporated into the preferred alcohol reaction assembly.

[0120] In accordance with a third aspect of the present inventions, analcohol detection assembly comprises an alcohol reaction chamber, areagent chamber in fluid communication with the alcohol reactionchamber, and a buffer chamber in fluid communication with the reagentchamber. The alcohol detection assembly further includes a bufferdispense plunger disposed within the buffer chamber for dispensingbuffer from the buffer chamber, through the reagent chamber, and intothe alcohol reaction chamber, where it hydrates dry reagent therein toproduce a reagent solution. The alcohol detection assembly furtherincludes a sample chamber in fluid communication with the alcoholreaction chamber, and is configured for containing and dispensing asample into the alcohol reaction chamber to produce a detectable alcoholsample solution. The alcohol detection assembly further includes anenergy source that is configured for transmitting an energy beam throughthe alcohol reaction chamber, an energy detector configured forreceiving the energy beam from the alcohol reaction chamber andoutputting a signal based on the received energy beam; and processingcircuitry configured for determining the presence of alcohol within thesample based on the output signal.

[0121] In a non-limiting preferred embodiment, the energy source cancomprise an optical source, e.g., a light emitting diode (LED), theenergy detector can comprise an optical detector, e.g., a silicon diodedetector, and the processing circuitry can comprise a central processorunit (CPU). The preferred alcohol detection assembly can furthercomprise a splitter for splitting energy from the energy source into theenergy beam and a reference energy beam that bypasses the alcoholreaction chamber, a reference energy detector for receiving thereference energy beam, and outputting a reference signal based on thereference energy beam, and a controller configured for using thereference output signal for maintaining the magnitude of the energy beamat a substantially uniform level.

[0122] The preferred alcohol detection assembly can also comprises acalibrator chamber in fluid communication with the alcohol reactionchamber, and a calibrator dispense plunger disposed within thecalibrator chamber for dispensing a predetermined quantity of alcoholfrom the calibrator chamber into alcohol reaction chamber. In this case,the energy source can be configured for transmitting an initial energybeam through the alcohol reaction chamber, energy detector can beconfigured for receiving the initial energy beam from the alcoholreaction chamber, and outputting an initial signal based on the initialreceived energy beam, and the processing circuitry can be configured forcalibrating the alcohol detection assembly based on the initial outputsignal. Previously described features can also be incorporated into thepreferred alcohol detection assembly.

[0123] In accordance with a fourth aspect of the present inventions, amethod of detecting the presence of alcohol in a sample comprisesflowing buffer from a buffer chamber through a reagent chamber toproduce and dispense a reagent solution into an alcohol reactionchamber, and dispensing the sample within the alcohol reaction chamberto produce an alcohol detectable sample solution. The method furthercomprises transmitting energy through the alcohol detectable samplesolution, receiving the energy from the alcohol detectable samplesolution, and determining a presence of alcohol within the sample basedon the received energy.

[0124] In a non-limiting preferred method, the alcohol detectable samplesolution is mixed to complete reaction between the sample and thereagent solution. The transmitted energy can be optical energy, in whichcase, the detectable alcohol sample solution may comprise an alcoholindicator exhibiting an optical absorbance value in the presence of thetransmitted optical energy, and the presence of alcohol in the samplecan be determined by determining the optical absorbance value based onthe optical energy received. The alcohol indicator may be nicotinamideadenine dinucleotide with high energy hydrogen (NADH), in which case,the reagent solution may comprise alcohol dehydrogenase (ADH) andnicotinamide adenine dinucleotide (NAD), and detectable alcohol samplesolution can be produced by reacting the NAD and the sample alcohol inthe presence of the ADH to produce the NADH. The optical absorbancevalue of the alcohol indicator can be proportional to the quantity ofalcohol reacted with the reagent solution, in which case, the preferredmethod may further comprise determining a concentration of the alcoholin the sample based on the optical absorbance value of the alcoholindicator. The preferred method may further comprise calibrating priorto dispensing the sample within the reagent solution.

[0125] In accordance with a fifth aspect of the present inventions, amethod of detecting the presence of alcohol in a sample comprisesflowing buffer from a buffer chamber through a reagent chamber toproduce and dispense a reagent solution within an alcohol reactionchamber, and dispensing the sample within the alcohol reaction chamberto produce an alcohol detectable sample solution having an alcoholindicator. The method further comprises determining an optical energyabsorbance of the alcohol indicator at a specified optical wavelength,and determining a presence of the alcohol in the sample based on theoptical energy absorbance measurement.

[0126] In a non-limiting preferred method, the alcohol indicator cancomprise nicotinamide adenine dinucleotide with high energy hydrogen(NADH), in which case, the reagent solution can comprise alcoholdehydrogenase (ADH) and nicotinamide adenine dinucleotide (NAD), whichreacts with the sample alcohol to produce the NADH. In the preferredmethod, the optical absorbance value of the alcohol indicator can beproportional to a quantity of alcohol reacted with the reagent solution,in which case, the concentration of the alcohol in the sample can bebased on the optical absorbance value of the alcohol indicator. Thesample alcohol concentration can be determined by dispensing apredetermined quantity of alcohol from a calibrator chamber into thealcohol reaction chamber prior to dispensing the sample, therebyproducing an alcohol detectable calibrator solution having a knownalcohol concentration C, and measuring a first optical absorbance valueA₀ of the reagent solution. a second optical absorbance value A₁ of thealcohol detectable calibration solution, and a third optical absorbancevalue A₃ of the alcohol detectable sample solution, at the specificwavelength, wherein the sample alcohol concentration is determined inaccordance with the factor C(A₂−A₀)/(A₁−A₀). The specified wavelengthused in the preferred method to determine absorbance of the solutionscan be an ultraviolet wavelength, e.g., 365 nm.

BRIEF DESCRIPTION OF THE DRAWINGS

[0127] In order to better appreciate how the above-recited and otheradvantages and objects of the present inventions are obtained, a moreparticular description of the present inventions briefly described abovewill be rendered by reference to specific embodiments thereof, which areillustrated in the accompanying drawings. Understanding that thesedrawings depict only typical embodiments of the invention and are nottherefore to be considered limiting of its scope, the invention will bedescribed and explained with additional specificity and detail throughthe use of the accompanying drawings in which:

[0128]FIG. 1 is a front-right perspective view of an on-site analytetesting system constructed in accordance with a preferred embodiment ofthe present inventions, wherein the testing system comprises a portabletest console and a loaded single-use disposable test loaded cassetteassembly;

[0129]FIG. 2 is a rear-right perspective view of the cassette assembly;

[0130]FIG. 3 is a front-right perspective view of the cassette assembly;

[0131]FIG. 4 is a bottom-left perspective view of the cassette assembly;

[0132]FIG. 5 is a top perspective view of the cassette assembly;

[0133]FIG. 6 is a front-left perspective view of the inner components ofthe test console with cassette assembly;

[0134]FIG. 7 is a front-right perspective view of the inner componentsof the test console with the cassette assembly;

[0135]FIG. 8 is a rear-right perspective view of the inner components ofthe test console with the cassette assembly;

[0136]FIG. 9 is a top perspective view of the inner components of thetest console with the cassette assembly;

[0137]FIG. 10 is a bottom-front perspective view of the inner componentsof the test console with the cassette assembly;

[0138]FIG. 11 is a bottom-rear perspective view of the inner componentsof the test console with the cassette assembly;

[0139]FIG. 12 is a schematic block diagram of various components of thetesting system and their interaction with a central processor unit(CPU);

[0140]FIG. 13 is a rear-left perspective view of the inner components ofthe test console without the cassette assembly, wherein a cassettecarriage is shown fully loaded into the test console;

[0141]FIG. 14 is a rear-right perspective view of the inner componentsof the test console without the cassette assembly, wherein the cassettecarriage is shown fully deployed from the test console;

[0142]FIG. 15 is a close-up perspective view of a cassette loadingassembly and a rotary valve drive assembly used in the test console;

[0143]FIG. 16 is a close-up perspective view of the test console portionof a sample collection assembly, and particularly, a vacuum port driveassembly;

[0144]FIG. 17 is a perspective view of the cassette portion of thesample collection assembly associated, and particularly, an oralaspirator, sample collection chamber, and flexible conduit, wherein acover/extended handle is shown used as a cover;

[0145]FIG. 18 is a perspective view of the oral aspirator, samplecollection chamber, and flexible conduit, wherein the cover/extendedhandle is shown used as an extended handle;

[0146]FIG. 19 is a longitudinal sectional view of the oral aspirator;

[0147]FIG. 20 is a perspective view of a bottom chamber base used toconstruct the sample collection chamber;

[0148]FIG. 21 is a perspective view of a top chamber cap used toconstruct the sample collection chamber;

[0149]FIG. 22 is a cut-away perspective view of the bottom chamber base;

[0150]FIG. 23 is a cut-away perspective view of the top chamber cap;

[0151]FIG. 24 is a perspective view of the cassette portion of a samplemixing assembly;

[0152]FIG. 25 is a perspective view of the buffer chamber and mixingchamber of the sample mixing assembly;

[0153]FIG. 26 is a cut-away perspective view of the buffer chamber andmixing chamber;

[0154]FIG. 27 is a cutaway perspective view of the sample mixingassembly shown in a home position;

[0155]FIG. 28 is a cutaway perspective view of the sample mixingassembly shown in a pre-sample and buffer dispensing position;

[0156]FIG. 29 is a cutaway perspective view of the sample mixingassembly shown in a buffered sample solution mixing position;

[0157]FIG. 30 is a cutaway perspective view of the sample mixingassembly shown in a pre-buffered sample solution dispensing position;

[0158]FIG. 31 is a cutaway perspective view of the sample mixingassembly shown in a post-buffered sample solution dispensing position;

[0159]FIG. 32 is a perspective view of a buffer plunger for use in themixing assembly;

[0160]FIG. 33 is a cutaway perspective view of the buffer plunger;

[0161]FIG. 34 is a perspective view of a sample dispense plunger for usein the mixing assembly;

[0162]FIG. 35 is a cutaway perspective view of the sample dispenseplunger;

[0163]FIG. 36 is a perspective view of a buffered sample dispenseplunger for use in the mixing assembly;

[0164]FIG. 37 is a cutaway perspective view of the buffered sampledispense plunger;

[0165]FIG. 38 is a close-up perspective view of the test console portionof the mixing assembly, and particularly, the sample and buffer driveassemblies;

[0166]FIG. 39 is a front-left perspective view of the cassette portionof an immunoassay flow assembly;

[0167]FIG. 40 is a rear-left perspective view of the cassette portion ofthe immunoassay flow assembly;

[0168]FIG. 41 is a perspective view of a distribution chamber for use inthe immunoassay flow assembly;

[0169]FIG. 42 is a cutaway perspective view of the distribution chamber;

[0170]FIG. 43 is a perspective view of a buffer chamber for use in theimmunoassay flow assembly;

[0171]FIG. 44 is a cutaway perspective view of the buffer chamber;

[0172]FIG. 45 is a front-right perspective view of the cassette portionof a sample/buffer flow assembly for use in the immunoassay flowassembly;

[0173]FIG. 46 is a rear-right perspective view of the cassette portionof the sample/buffer flow assembly;

[0174]FIG. 47 is a side view of the cassette portion of thesample/buffer flow assembly;

[0175]FIG. 47A is a longitudinal-sectional view taken along the line47A-47A of FIG. 47;

[0176]FIG. 47B is a magnified view taken along the line 47B of FIG. 47A;

[0177]FIG. 48 is another side view of the cassette portion of thesample/buffer flow assembly;

[0178]FIG. 48C is a longitudinal-sectional view taken along the line48C-48C of FIG. 48;

[0179]FIG. 48D is a magnified view taken along the line 48D of FIG. 48C;

[0180]FIG. 49 is a bottom view of a rotary valve for use in thesample/buffer flow assembly;

[0181]FIG. 50 is a rear-left perspective view of the rotary valve;

[0182]FIG. 51 is a top view of the rotary valve;

[0183]FIG. 52 is one perspective view of a rotor for use in the rotaryvalve;

[0184]FIG. 53 is another perspective view of the rotor;

[0185]FIG. 53A is a magnified view taken along the line 53D of FIG. 53;

[0186]FIG. 54 is a perspective view of a rotor core used to constructthe rotor;

[0187]FIG. 55 is front-left perspective view of the cassette portion ofthe sample/buffer flow assembly, particularly showing sampledistribution and venting flow paths when the rotary valve is clocked ina sample distribution configuration;

[0188]FIG. 56 is rear-left perspective view of the cassette portion ofthe sample/buffer flow assembly, particularly showing the sample anddistribution venting flow paths when the rotary valve is clocked in thesample distribution configuration;

[0189]FIG. 57 is a longitudinal-sectional view of the rotary valve,particularly showing distribution channels;

[0190]FIG. 58 is a front-left perspective view of the cassette portionof the sample/buffer flow assembly, particularly showing sample dispenseflow paths when the rotary valve is clocked in a sample flowconfiguration;

[0191]FIG. 59 is a longitudinal-sectional view of the rotary valve,particularly showing sample dispense channels;

[0192]FIG. 60 is a side view of the cassette portion of thesample/buffer flow assembly, particularly showing a sample dispensechannel;

[0193]FIG. 61 is a front-left perspective view of the cassette portionof the sample/buffer flow assembly, particularly showing buffer dispenseflow paths when the rotary valve is clocked in a buffer pre-washconfiguration;

[0194]FIG. 62 is a rear-left perspective view of the cassette portion ofthe sample/buffer flow assembly, particularly showing the bufferdispense flow paths when the rotary valve is clocked in the bufferpre-wash configuration;

[0195]FIG. 63 is a side view of the cassette portion of thesample/buffer flow assembly, particularly showing the buffer dispensechannel;

[0196]FIG. 64 is a rear-left perspective view of the cassette portion ofthe sample/buffer flow assembly, particularly showing the bufferdispense flow paths when the rotary valve is clocked in a bufferpost-wash configuration;

[0197]FIG. 65 is a side view of the cassette portion of thesample/buffer flow assembly, particularly showing the buffer dispensechannel;

[0198]FIG. 66 is a rear-right perspective view of the test consoleportion of the sample/buffer flow assembly mounted within the main baseof the test console;

[0199]FIG. 67 is a perspective view of the test console portion of thesample/buffer flow assembly;

[0200]FIG. 68 is a perspective view of a motor drive assembly for use inthe sample/buffer flow assembly;

[0201]FIG. 69 is a perspective view of a reaction chamber for use in animmunoassay reaction assembly;

[0202]FIG. 70 is a cutaway perspective view of the reaction chamber;

[0203]FIG. 71 is a cross-section of a frit tool assembly used to installfrits within a plurality of reaction chambers;

[0204]FIG. 72 is a cross-section of one bore of the frit tool assembly,particularly showing the newly cut frit within the die plate;

[0205]FIG. 73 is a cross-section of the frit tool assembly bore,particularly showing the frit passing through the compression plate;

[0206]FIG. 74 is a cross-section of the frit tool assembly bore,particularly showing the frit mounted within the reaction chamber;

[0207]FIG. 75 is a front-right perspective view of the immunoassayreaction assembly for use in the immunoassay flow assembly;

[0208]FIG. 76 is a rear perspective view of the immunoassay reactionassembly;

[0209]FIG. 77 is a front view of the immunoassay reaction assembly;

[0210]FIG. 78 is a front view of the immunoassay flow assembly,particularly showing the filling of the distribution chambers withsample during the sample distribution process;

[0211]FIG. 79 is a rear view of the immunoassay flow assembly,particularly showing the dispensing of buffer from the buffer chambersduring the buffer pre-wash process;

[0212]FIG. 80 is a front view of the immunoassay flow assembly,particularly showing the dispensing of sample from the distributionchambers during the sample dispense process;

[0213]FIG. 81 is a rear view of the immunoassay flow assembly,particularly showing the dispensing of buffer from the buffer chambersduring the buffer post-wash process;

[0214]FIG. 82 is a top perspective view of the immunoassay scanningassembly and associated cassette for use within the test console;

[0215]FIG. 83 is a front-right perspective view of the immunoassayscanning assembly, particularly showing a scanner head mechanism in anend position;

[0216]FIG. 84 is a front-right perspective view of the immunoassayscanning assembly, particularly showing the scanner head mechanism in ahome position;

[0217]FIG. 85 is a front view of the immunoassay scanning assembly;

[0218]FIG. 86 is a schematic diagram of an optical excitation assemblyand optical detection assembly associated with an optical read cell ofthe immunoassay reaction assembly;

[0219]FIG. 87 is a diagram plotting the gated voltage levels of ameasured reaction within the channels of the immunoassay reactionassembly as measured by the immunoassay scanning assembly during asingle scan;

[0220]FIG. 88 is a diagram plotting the voltage level of a measuredreaction within a channel of the immunoassay reaction assembly duringthe buffer pre-wash, sample flow, and buffer post wash processes;

[0221]FIG. 89 is a rear-right perspective view of the cassette portionof an alcohol reaction assembly mechanically associated with thecassette portion of the immunoassay flow assembly;

[0222]FIG. 90 is a front-left perspective view of the cassette portionof an alcohol reaction assembly mechanically associated with thecassette portion of the immunoassay flow assembly;

[0223]FIG. 91 is front perspective view of the cassette portion of thealcohol reaction assembly;

[0224]FIG. 92 is a rear perspective view of the cassette portion of thealcohol reaction assembly;

[0225]FIG. 93 is a top view of the cassette portion of the alcoholreaction assembly;

[0226]FIG. 93A is a longitudinal-sectional view taken along the line93A-93A of FIG. 93;

[0227]FIG. 94 is a front view of the cassette portion of the alcoholreaction assembly;

[0228]FIG. 94A is a cross-sectional view taken along the line 94D-94D ofFIG. 94;

[0229]FIG. 95 is a cross-sectional view of the cassette portion of thealcohol reaction assembly when the rotary valve is in the sampleflow/buffer post-wash configuration;

[0230]FIG. 96 is a cross-sectional view of the cassette portion of thealcohol reaction assembly when the rotary valve is clocked in the sampledistribution/buffer pre-wash configuration;

[0231]FIG. 97 is a perspective view of a heater assembly for use in atemperature control assembly of the test console;

[0232]FIG. 98 is a perspective view of the inside of a front panel usedto construct a cassette case of the cassette assembly;

[0233]FIG. 99 is a perspective view of the front panel with the cassetteportion of the immunoassay flow assembly mounted therein;

[0234]FIG. 100 is a perspective view of the inside of a rear panel usedto constructed the cassette case;

[0235]FIG. 101 is a perspective view of the rear panel with the cassetteportion of the immunoassay flow assembly mounted therein;

[0236]FIG. 102 is a flow diagram illustrating the initialization processof the system; and

[0237]FIG. 103 is a flow diagram illustrating the administration,operation, and recall modes of the system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0238] With reference to FIG. 1, an on-site analyte testing system 100will be briefly described. The system 100 utilizes flow immunoassaytechnology and the collection of saliva as a specimen to screen,quantitatively, or semi-quantitatively detect the presence of any numberof analytes, and specifically drugs and beverage alcohol (both illegaland legal), in a test subject. For the purposes of this specification, atest subject is any human or animal whose bodily fluids (in this case, asaliva sample) is to be collected and analyzed for drug/alcohol contentusing the system 100. A screening test is a test that provides forquantitation of results with sufficient accuracy and precision to permitpositive determination of whether the level of analyte present in thesample is at or below a predefined cutoff level, in which case the testis declared to be a negative result, or whether the analyte is above thepredefined cutoff level, in which case the test is declared to be apositive result. A quantitative test is a test that provides forlegally-defined quantitation of results for an analyte over a definedrange (for ethanol 0.04-0.20%) at or above defined accuracy (for ethanol≧95%) and precision (for ethanol ≧95%) levels. A semi-quantitative testis a test that provides for quantitation of results for an analyte overmanufacturer-defined limits of accuracy, precision, and range ofresults.

[0239] The system 100 is a relatively small self-contained device, andthus, can be conveniently used in a broad range of areas, including longterm therapeutic drug monitoring, disease-state testing, wellness-healthscreening, and all rapid diagnostic testing where a non-invasivespecimen collection and/or rapid analytic result is desired. In thepreferred embodiment, the system 100 can selectively provide up to tenspecific immunoassay tests in a single test panel on a single, smallvolume, saliva sample. The system 100 manages all functions related tothe running of a test on a subject, including automatic quality controlvalidation, specimen collection, specimen adequacy test, specimenprocessing, reagent addition, optical readout, test result analysis anda quantitative results printout with interpretation. The system 100automatically generates a hardcopy of the test results andinterpretation to provide the necessary documentation of test results.Thus, the system 100 is fully or semi-automated in that minimalinteraction by the operator is required.

[0240] The preferred embodiment of the system 100 provides the followingadvantages: (1) it is user friendly to non-technical personnel; (2) itcollects a single specimen and generates ten test results in less thanten minutes; (3) it is non-invasive; (4) it generates blood-equivalenttests results in non-medical environments equal to centralizedlaboratory test results; (5) provides quantitative and evidentiaryresults; (6) can be customized to a broad list of applications by usingmultiple panels with multiple formats; (7) it is completely automatedand requires no user intervention, thereby providing for legallydefensible results; (8) reagents used in system can be stored for arelatively long period of time; (9) it can be applied to saliva, urine,and whole blood or plasma assays; and (10) it is portable in that it canbe carried and transported by a single person and can fit into a compactplace. Succinctly, the system is a highly sensitive, rapid,non-invasive, easy-to-use, on-site diagnostic tool.

[0241] The preferred system 100 generally includes a relatively small,portable test console 102 and a single-use disposable test cassetteassembly 150 (shown in FIGS. 2-5), which is received by the test console102 via a cassette port 106, as will be described in further detailbelow. The test console 102 includes a case 108, which contains all ofthe componentry (e.g., the circuitry, motors, sensors, detection andillumination devices, etc.) necessary to effect the control,electromechanical, optical, and computational functions performed on thecassette assembly 150 and essential for the analysis of the analyteswithin the test subject's saliva sample. In the illustrated embodiment,the case 108 is structurally divided into a bottom case portion 110 anda top case portion 112. As can be seen in FIGS. 6-11, the test console102 also includes a main base 114, which provides the necessary supportfor the inner components of the console 102, integrating the assemblyinto a single unit. In the illustrated embodiment, the main base 114includes a top flange 116, a bottom flange 118, and two side flanges 120and 122, which are arranged to form a hollow three dimensionalrectangular rigid structure mounted inside the bottom case portion 110.The main base further includes a distribution flange 124 on whichvarious motors and associated components are distributed, and a pair ofspacer flanges 126 to space the main base 114 from the bottom caseportion 110.

[0242] Referring to FIGS. 2 and 3, the cassette assembly 150 includes anexternal sample collection interface device, and specifically an oralaspirator 402, and an associated flexible sample collection conduit 410,which is used to collect saliva from a subject via aspiration. Thecassette assembly 150 further comprises a chemistry cassette 152 thatincludes a case 154, which, for purposes of reference, has a front 156,rear 158, top 160, and bottom 162. The cassette case 154 houses all thechemical reagents needed to perform a panel of immunoassay tests fordrugs, as well as an enzymatic test for ethanol, on the test subject'ssaliva sample. In the illustrated embodiment, the cassette case 154contains prepackaged quantities of lyophilized stable solid reagents andstabilized liquid buffer reagents having a shelf-life of twelve monthsunder defined storage conditions. The cassette case 154 further containsall required components to provide for defined flow rate and for opticalquantitation of the alcohol concentration and fluorimetricsemiquantitation of the drug levels. The cassette case 154 also containsall materials, surfaces, chambers, and components that will be wetted bythe saliva sample by aspiration into the chemistry cassette 152 andsubsequently analyzed by the test console 102. The cassette case 154 isfurther designed to self-contain all chemical reagents and thebiological sample after their chemical reaction, and to treat the salivasample with an antibacterial to obviate any biological hazard of thephysiological sample. Other than the chemical reagents, the chemistrycassette 152 is made entirely of common injection-molded polymers(plastics) and aluminum foil. Therefore it can be disposed of simply assolid waste.

[0243] Thus, the chemistry cassette 152, when installed within the testconsole 102, enables it to identify a multitude of oral fluid analytesand is available in a variety of formats to provide the various marketswith the specific test panels they require. For example, the chemistrycassette 152 may provide a five drug test panel to screen orsemi-quantitatively identify the National Institute on Drug Abuse (NIDA)required drugs-of-abuse, which is currently identified as cocaine,opiates (heroin, morphine, and codeine), phencyclidine (PCP),amphetamines/methamphetamines, and marijuana (tetrahydrocannabinol orTHC). The chemistry cassette 152 also provides screening orsemi-quantitative analysis of beverage alcohol (ethanol or EtOH). Asanother example, the chemistry cassette 152 may provide up to ten testsfor overdose or disease panel testing. Thus, the chemistry cassette 152can be customized to any one of a variety of applications. Thus, thecombination of the test console 102 and chemistry cassette 152 providesfor a fully operational flow immunoassay analyte tester.

[0244] It should be noted that a confirmation cassette, which does notperform any immunoassay tests, can be optionally used with the testconsole 102 to merely collect the aspirated saliva sample from the testsubject. Typically, it will be used subsequent to the administration ofa drug-of-abuse test on a subsequently collected saliva sample in orderto confirm the results of the test. Confirmatory tests use advancedinstrumentation to provide for sufficiently specific results toeliminate the possibility of interfering or cross-reacting species thatmight provide incorrect results, either false-positive or false-negativeresults, when tested with a screening test using less complex and moreinexpensive technology. For example, for use by its agencies, the U.S.Government requires that screening tests for drug-of-abuse be confirmedwith a test specifically incorporating gas chromatography/massspectrometry for confirmation of results.

[0245] Having generally described the system 100, the various assemblieslocated in the chemistry cassette 152 and/or test console 102 will nowbe described. It should be noted, however, that the functionalorganization of this discussion into various assemblies is provided tofacilitate in the understanding of the system 100, and is not meant tolimit the structure of the assemblies in any way. For example,assemblies located in both the chemistry cassette 152 and the testconsole 102 may be divided into a cassette portion and a tester portionin the subsequent discussion. This does not mean, however, that thecombination of these two portions cannot be considered a singleassembly. Also, many of the components described herein bear on thefunctionality of several assemblies. Thus, the organization ofcomponents into a particular assembly does not mean that any suchcomponents cannot be considered a part of another assembly.

[0246] I. Electrical Assembly

[0247] Referring to FIG. 12, an electrical assembly 200 provides thenecessary electrical and sensing functions to the system 100. To thisend, the electrical assembly 200 comprises an AC/DC power supply 202that plugs into normal AC power mains (85-240 VAC, 50-60 Hz) andsupplies a nominal single DC voltage of 12 VDC (or multiple DC voltagesof +5 and ±15 VDC) to the test console 102 at sufficient current toprovide electrical power for all operations of the test console 102. Allpower requirements of the test console 102 may also be supplied by anexternal battery (not shown) of a sufficient ampere-hours rating tosupply electrical power for all operation of the test console 102 whenremote from AC supplies, such as on a ship, in an ambulance, or in apolice car.

[0248] In the illustrated embodiment, the test console 102 providessufficient internal shielding and power supply decoupling capacitors(not shown) to minimize susceptibility to external interference causedby electrostatic (ESI), electromagnetic (EMI) and radiofrequency-interference (RFI) sources. The test console 102 is alsosufficiently shielded and filtered to minimize generation ofinterference from ESI, EMI or RFI sources within the instrument. Thetest console 102 thus produces no more electrical noise than othercommon household appliances, such as television receivers or homecomputers. Analog and digital grounds are kept separate through the testconsole 102 and only joined at a single reference point within thedevice to minimize noise and possible error sources caused by potentialground loops within the test console 102. Similarly, all low-level, highimpedance inputs are shielded and isolated to minimize noise sourceswithin the test console 102.

[0249] The electrical assembly 200 further includes a central processorunit (CPU) 204, which controls all operations of the test console 102,with the exception of the cassette temperature controller (describedbelow), which is under dedicated hardware control. In this regard, theCPU 204 is coupled via an input/output (I/O) controller 206 to amultitude of sensors 208 and motors 210 located throughout the testconsole 102. In this manner, the CPU 204 can control the motors 210 toeffect the various functions performed within the test console 102, andcan read the sensors 212 to determine the status of such functions. Aswill also be described in further detail below, the CPU 204 alsoperforms intelligence functions, such as performing an analysis on thesample and interfacing with the operator.

[0250] II. Cassette Loading Assembly

[0251] Referring to FIGS. 13 and 14, the system 100 comprises a cassetteloading assembly 300, the purpose of which is to allow the operator toload and unload the chemistry cassette 152 into and out of the testconsole 102. The cassette loading assembly 300 comprises a cassettecarriage 302 for receiving the chemistry cassette 152. To this end, thecassette carriage 302 includes a front support flange 304 and a bottomflange 306, which are profiled to seat and receive the chemistrycassette 152. To ensure that the chemistry cassette 152 is firmlyseated, the cassette carriage 302 comprises a pair of homing pins 308extending from the front support flange 304, which are sized and spacedto mate with a corresponding pair of homing pin holes 164 formed in thefront 156 of the cassette case 154 (see FIG. 3). As can be seen by FIGS.13 and 14, the cassette carriage 302 linearly translates in relation tothe main base 114. To this end, the cassette loading assembly 300further includes a rail 307 (shown in FIGS. 8 and 15), which is suitablymounted on the top main base flange 116, and a mating runner 309 (shownalso in FIGS. 8 and 15), which is suitably mounted to the bottom of thecassette carriage 302, thus allowing the cassette carriage 302 tosmoothly ride on the main base 114 between a fully extended position(FIG. 13 ) and a fully closed or home position (FIG. 14). The cassettecarriage 302 includes a door 310 mounted to its end, such that when thecassette carriage 302 is fully loaded, the door 310 is shut against thecassette port 106, forming a light block that substantially eliminatesstray ambient light from the interior of the test console 102, theimportance of which will be described in further detail below.

[0252] Referring also to FIG. 15, the cassette loading assembly 300further includes a cassette loading drive assembly 312, which automatesthe reciprocal movement of the cassette carriage 302 in relation to themain base 114. The cassette loading drive assembly 312 includes arotational stepper motor 314 with an associated drive pulley 316, and adrive screw 318 with an associated idler pulley 320. The drive screw 318includes a threaded portion 322 (best shown in FIG. 14) and opposingunthreaded portions 324 (only one shown in FIG. 13). The cassetteloading drive assembly 312 further includes a drive belt (not shown)mounted around the respective drive and idler pulleys 316 and 320 foroperably connecting the stepper motor 314 to the drive screw 318. Thecassette loading drive assembly 312 further includes a motor mount 328for affixing the motor 314 to the side main base flange 122, and a pairof drive screw positioners 330 (shown also in FIG. 8) having apertures332 in which the unthreaded ends 324 of the drive screw 324 are free torespectively rotate. The drive screw positioners 330 are suitablymounted to the top main base flange 116, so that the rotating drivescrew 318 is linearly fixed relative to the main base 114. The cassetteloading drive assembly 312 further includes a threaded flange 334, whichis suitably mounted to the exterior of the cassette carriage 302. Thethreaded flange 334 includes a longitudinally disposed threaded hole 336through which the threaded portion 322 of the drive screw 318 isdisposed. Thus, operation of the motor 314 rotates the drive pulley 316,which in turn rotates the idler pulley 320 and thus the drive screw 318via drive belt. The cassette carriage 302 is then linearly translatedwith respect to the main base 114. Under control of the CPU 204 and I/Ocontroller 206 (see FIG. 12), the motor 314 can be reciprocally operatedto alternately translate the cassette carriage 302 between the fullyloaded and fully extended positions.

[0253] Having described the structure of the cassette loading assembly300, its operation will now be described. In its home position (FIG.13), the empty cassette carriage 302 is fully loaded into the testconsole 102 and the door 310 is shut against the cassette port 106 ofthe test console 102 (FIG. 1). The cassette carriage 302 is ejected bysemi-automatically operating (i.e., prompted by the operator) thecassette loading drive assembly 312 to fully extend the cassettecarriage 302 out the cassette port 106, allowing the operator to mountthe cassette 152 within the cassette carriage 302. The cassette 152 isthen loaded into the test console 102 by semi-automatically operatingthe cassette loading drive assembly 312 to fully insert the cassettecarriage 302 with the cassette 152 into the cassette port 106, returningthe cassette carriage 302 to its home position. The cassette 152 can beejected from the tester by again semi-automatically operating thecassette loading drive assembly 312 to fully extend the cassettecarriage 302 and cassette 152 out the cassette port 106, allowing theoperator to remove the cassette 152 from the cassette carriage 302. Afully extended cassette carriage sensor, fully inserted cassettecarriage sensor, and door shut sensor (shown generally as sensors 208 inFIG. 12) are used to ensure that the afore-described steps have beenfully effected.

[0254] III. Self-Customizing Assembly

[0255] Referring to FIG. 15, the system 100 comprises a self-customizingassembly 350, the purposes of which is to customize one or moreoperational parameters of the system as dictated by the chemistrycassette 152. To this end, the self-customizing assembly 350 comprises abarcode read assembly 352 and a customization assembly 354.

[0256] The purpose of the barcode read assembly 352 is to identifyinformation associated with the chemistry cassette 152. To this end, thebarcode read assembly 352 includes a unique barcode 356, which isaffixed to the rear 158 of the cassette case 154 (shown in FIG. 2), andwhich contains information specific to the chemistry cassette 152. Thebarcode read assembly 352 includes a standard barcode reader 358, whichis mounted to the top main base flange 116 via a mount 360, and isoptically aligned with the barcode 356 when the chemistry cassette 152is loaded within the test console 102 (FIG. 9). In the illustratedembodiment, the barcode 356 contains the following information: (1) typeof cassette (e.g., NIDA drugs-of-abuse and alcohol cassette,confirmation cassette, etc.); (2) date of manufacture; (3) variouslot-specific calibration information for each of the test channels; and(4) checksum code.

[0257] The customization assembly 354 comprises circuitry, andspecifically the CPU 204, which is electrically coupled to the barcodereader 358 and modifies the operational parameters, and specifically thetesting parameters, of the system 100 based on the barcode information.The CPU 204 can optionally modify sample flow parameters within thesystem 100 by, e.g., operating various motors to provide for differentsample flow rates and volumes within the system 100 based on the type ofcassette indicated in the barcode. Optionally, information specificallyindicating the sample flow parameters can be contained within thebarcode, in which case, the CPU 204 need not infer the different flowrates and volumes from the type of cassette. In addition, the CPU 204can also calibrate a test panel using the test calibration informationcontaining with the barcode. Further details on the customization of thesystem 100 will be described below.

[0258] The CPU 204 is also configured to operate the barcode reader 358to destroy the barcode checksum code when the cassette 152 is ejectedfrom the test console 102. Thus, if the barcode information and thechecksum code do not correspond, the chemistry cassette 152 will not beable to be used, thereby preventing inadvertent or intentional reuse ofan invalid cassette 152. Also, the CPU 204 will prevent use of thecassette 152 if it is expired, e.g., 12 months after the date ofmanufacture.

[0259] In operation, when the cassette 152 is loaded into the testconsole 102, the barcode reader 358 is automatically operated to readthe information from the barcode 356 disposed on the cassette 152. Thisinformation is then processed by the test console 102, and specifically,the CPU 204. If the cassette 152 has expired or has been previouslyused, the CPU 204 will operate the cassette loading assembly 300 toeject the chemistry cassette 152. Otherwise, the CPU 204 will customizethe operational parameters of the system 100 based on the barcodeinformation. After completion of the test, the CPU 204 operate thecassette loading assembly 300 to eject the cassette 152. Additionally,as cassette 152 is ejected from the test console 102, the CPU 204operates the barcode reader 358 to erase the checksum code from thebarcode 356, so that the cassette 152 cannot be reused.

[0260] IV. Sample Collection Assembly

[0261] Referring to FIGS. 2, 6, and 16, the system 100 comprises asample collection assembly 400, the purpose of which is to collect therequired amount of saliva (in the illustrated embodiment, 350±35 μL)semi-automatically by vacuum aspiration from the mouth of the testsubject. That is, the sample collection assembly 400 automatically drawssaliva sample into the cassette 152, measures the total volumeaccumulated within the cassette 152, and notifies the operator when anadequate volume of sample has been accumulated.

[0262] A. Sample Collection Assembly—Cassette Portion

[0263] Referring specifically to FIGS. 17-19, the portion of the samplecollection assembly 400 associated with the cassette assembly 150 isillustrated. The sample collection assembly 400 includes theafore-mentioned oral aspirator 402, which includes a hand piece 404, asample collection tip 406 and a cover/extended handle 408, theafore-mentioned flexible conduit 410, and a sample collection chamber412. As illustrated in FIG. 2, the oral aspirator 402 and conduit 410are external to the cassette 152, whereas the sample collection chamber412 is internal to the cassette 152.

[0264] The hand piece 404 is composed of hollow rigid or semi-rigidmaterial of a suitable length and diameter. For example, the hand piece404 can be composed of white-colored, injection molded ABS plastic, thatis 15 cm in length, and 1 cm in diameter at a handle 414 that narrows to0.5 cm diameter at a tip 414. To provide for the best ergonomic use ofthe hand piece 404 in the mouth of the test subject, the handle 414 isbent to a gentle obtuse angle, e.g., 150° at a distance of 5 cm from thetip 414, and has two opposing molded finger grips 418, e.g., 10 cm fromthe tip 414.

[0265] The cover/extended handle 408 is also composed of a hollow rigidor semi-rigid material of a suitable length and diameter to fit overeither the tip 414 of the hand piece 404 (FIG. 17) or the handle 414 ofthe hand piece 404 (FIG. 18). For example, the cover/extended handle 408can be composed of a white-colored, injection molded ABS plastic that is5 cm in length and 1 cm in diameter. As a cover, it can be initiallyplaced over the sample collection tip 406 to keep it clean duringstorage and just prior to use, and can be held in place by a positivesnap-action ribbed holder 420. As an extended handle, it can be removedfrom the sample collection tip 406 and slipped onto the handle 414 ofthe hand piece 404, where it is held in place by another positivesnap-action ribbed holder 422. Thus, the length of the hand piece 404 isextended in additional amount (e.g., for a total length of 19 cm to keepthe test subject's and operator's fingers away from the samplecollection tip 406, which will be coated with saliva. Following use, thecover/extended handle 408 can be replaced over the saliva-wetted tip 416to prevent accidental contact of the test subject and/or operator withpotentially biologically-hazardous saliva remaining on the tip 416.

[0266] The sample collection tip 406 has a size the allows it tocomfortably fit within a subject's mouth, and is constructed of anon-toxic, non-analyte absorbing material. In the illustratedembodiment, the sample collection tip 406 is cylindrical in shape with ahemidome-shaped top surface, and has a length of 9 mm and a diameter of7 mm. The sample collection tip 406 comprises a sample collection body424 composed of a hydrophilic material, such as a fused, nontoxic, highdensity polyethylene (HDPE) microporous material. The outer surface 426of the sample collection body 424 is treated with a surfactant, whichreduces the surface tension of the fluid in contact with the outersurface 426. Suitable proprietary surfactants for this purpose can beobtained from Porex Corporation located in Fairbum, Ga. Thus, theinterior of the microporous sample collection body 424 is hydrophobic,whereas its outer surface 426 is hydrophilic. When in contact, evenpartially, with a small pool of saliva in the mouth, the hydrophilicouter surface 426 of the sample collection body 424 is sufficient tocause capillary action to transport saliva into the hydrophobic interiorof the sample collection body 424. It is noted that with purelyhydrophobic tips, substantially the entire surface of the tip must be incontact with saliva in order to flow saliva into the interior of thetip, since exposing any portion of the hydrophobic tip surface to airwould tend to draw in the less viscous air.

[0267] Thus, a relatively small applied vacuum level, e.g., 350 mmHgabsolute at an air flow rate of 5-50 ml/min, has been found to besufficient to draw saliva from the microporous sample collection tip 406through the flexible conduit 410. This is advantageous in that a minimumair flow rate is necessary to maintain consistent oral fluid collection,since too high of a flow rate causes a greater volume of air to betransported through the system, requiring removal of greater volumes ofair in the sample collection chamber 412. Also, where loss of volatilecomponents in the saliva must be controlled, maintaining a constant,minimal flow of air through the sample collection assembly 400 at alltimes is advantageous.

[0268] The micropores 428 of the sample collection tip 406 are of asuitable diameter, e.g., 135 μm, to facilitate collection of the viscoussaliva from the interior surface of the mouth. These micropores 428 alsofunction as a large pore-size depth filter to prevent larger pieces offood, plaque or particles exogenous to the mouth from being aspiratedinto the small interior diameter of the flexible conduit 410, where theymight possibly clog it and prevent aspiration of the salivatherethrough. The sample collection tip 406 is bonded to the tip 416 ofthe hand piece 404 with a nontoxic, medical-grade cyanoacrylateadhesive. Specifically, the rear circular surface of the samplecollection tip 406 is bonded to the front surface of the hand piece tip416, thereby sealing the rear micropores of the sample collection tip406 and forcing air to flow from the sides and front surfaces of thesample collection tip 406, where saliva is likely to be located once thetip 406 is inserted into the mouth of the test subject for samplecollection.

[0269] Also, the central axis of the sample collection tip 406 containsa bore 428 into which one end of the flexible conduit 410 is insertedand bonded with a non-toxic, non-analyte absorbing material, preferablythe same as that used to bond the sample collection tip 406 to the handpiece tip 416. This double bonding with very strong adhesive causes thesample collection tip 406 to be held to the hand piece tip 416 with moreadhesive force than the sample collection tip's own cohesive forces.Thus, under extreme pressure, the sample collection tip 406 willfragment rather than come loose from the hand piece 404, therebyminimizing the risk of swallowing the sample collection tip 406.

[0270] The hollow-core flexible conduit 410 is made of a suitablenon-toxic hydrophobic slippery material, so that drugs, e.g., THC, willnot stick to its interior surface, and the flow of viscous liquid salivathrough the narrow-bore interior of the flexible conduit is facilitated.Pure polytetrafluoroethylene (PTFE or Teflon) has been found to besuitable for this purpose. To facilitate bonding of the flexible conduit410 to surfaces, such as the bore 428 of the sample collection tip 406,the outer surface of the PTFE can be etched to a depth of a fewangstroms thick with a hydrophilic surface. The inner diameter of theflexible conduit 410 is preferably selected based on the vacuum leveland flow rates, while maximizing retention of volatile ethanol in thesaliva sample as it is aspirated through the flexible conduit 410. Aninner diameter of, e.g., 0.5 mm has been empirically found to besuitable for a vacuum level of 350 mmHg absolute and an air flow rate ofbetween 5-50 ml/min. The thickness of the wall of the flexible conduit410 is preferably suitable to prevent kinking, which may otherwise clogthe bore of the flexible conduit 410, and thereby prevent collection ofthe saliva sample. Also, the specified wall thickness should providesufficient strength to prevent most persons from being able to stretchor part the material, thereby preventing sample collection. A wallthickness of 0.50 mm has been found to be suitable for this purpose. Thelength of the flexible conduit 410 is preferably suitable to facilitatecollection of the required volume of saliva from comfortably seated testsubjects when the test console 102 is placed on a bench-top. A length of45-60 cm has been found to be suitable for this purpose.

[0271] Referring to FIGS. 20 and 21, the sample collection chamber 412is composed of a suitable material, such as injection molded ABSpolymer, and is formed of a top chamber cap 430 and a bottom chamberbase 432, which are thermally welded together around theircircumference. The top chamber cap 430 includes a self-sealing vacuumport 434 within which there is tightly disposed a hydrophobic seal 436.In the illustrated embodiment, the seal 436 is composed of aself-sealing polyethylene membrane that comprises small-diameter poresthat are coated with a hydrophilic substance, such ascarboxymethlcellulose. When wetted, the hydrophilic pores rapidly swell,closing the pore interiors, thereby preventing liquid from passingthrough the membrane. This self-sealing vacuum port 434, thusfacilitates passing air, while preventing liquid or spray droplets frompassing from the cassette, which contains all saliva-wetted parts of thesystem 100, into the test console 102, which must remain dry in order toprevent even the remote possibility of electrical shock hazard. Theself-sealing vacuum port 434 also serves to keep the potentiallybiologically hazardous saliva from leaking out of the cassette 152 afterits disposal following use.

[0272] Referring further to FIGS. 22 and 23, the top chamber cap 430further includes a sample input port 438 within which the end of theflexible conduit 410 is bonded with a suitable material, such as amedical grade cyanoacrylate adhesive. The diameter of the input port 438is of a suitable value, e.g., 1.5 mm, to facilitate a tight fit with theflexible conduit 410. The sample input port 432 leads to an internalchamber 440 within the bottom chamber base 432, which in the illustratedembodiment, has a diameter of 1 cm and holds an interior volume of 0.5ml of saliva without wetting the self-sealing vacuum port 434. Theinternal chamber 440 has an inverted conical shape. Specifically, theinternal chamber 440 is cylinder-shaped at its upper rim and graduallynarrows to small diameter at its lower end, e.g., 0.5 mm, which leads toa sample dispense port 442 having the same diameter. So that the sampleinput port 438 is clocked in a predetermined rotational orientation withrespect to the chamber base 432, the chamber cap 430 and chamber base432 are provided with an alignment mechanism, and specifically a matingdetent 444 and slot 446. In this manner, the portion of the flexibleconduit 410 attached to the sample input port 438 will be consistentlypositioned adjacent a routing slot 175 formed on the top 160 of thecassette case 154, thereby allowing the flexible conduit 410 of thesample collection assembly 400 to be conveniently routed from the samplecollection chamber 412 to the exterior of the cassette case 154.

[0273] B. Sample Collection Assembly—Tester Portion

[0274] Having just described the portion of the sample collectionassembly 400 associated with the cassette assembly, the portion of thesample collection assembly 400 associated with the test console 102 willbe discussed. Referring to FIGS. 6 and 16, the sample collectionassembly 400 further includes a vacuum port connector 450, vacuum portdrive assembly 452, vacuum tubing 454, vacuum pump 456 with anassociated vacuum inlet filter 458, and a fluid sensor 460 (shown inFIG. 8).

[0275] The vacuum port connector 450 is composed of a compliant siliconerubber in the form of bellows, a compliant rim of which forms a tightvacuum seal when engaged with the cassette vacuum port 434. In theillustrated embodiment, the vacuum port connector 450 is 1.5 cm inlength, and 1 cm in diameter, with its compliant rim 2 mm in width. Thevacuum port connector 450 is engaged with the cassette vacuum port 434by the vacuum port drive assembly 452, which includes a linear steppermotor 462 and a motor mount 464. The motor 462 is mounted to the motormount 464, which is in turn mounted to the distribution flange 124. Thevacuum port drive assembly 452 further includes a threaded drive pin 466rotatably coupled to the motor 462, and a threaded positioner 468through which the drive pin 466 extends. The vacuum port drive assembly452 further includes a first drive flange 470 affixed to the threadedpositioner 468, and a second drive flange 472 on which the vacuum portconnector 450 is affixed. The second drive flange 472 is mounted to thefirst drive flange 470, which includes a runner 474 that slidinglyengages a rail 476 extending along the distribution flange 124.

[0276] Thus, the vacuum port drive assembly 452 can be operated to lowerthe vacuum port connector 450 from a home position (wherein the vacuumport connector 450 is disengaged with the cassette vacuum port 434 to apre-collection position (wherein the compliant rim of the connector 450and the cassette vacuum port 434 coincide and provide a tight seal. Asshown in FIGS. 2 and 5, a vacuum port access opening 166 is formed atthe top 160 of the cassette case 154, thereby allowing the vacuum portconnector 450 to engage the vacuum port 434 of the sample collectionchamber 412.

[0277] The other end of the vacuum port connector 450 is connected tothe vacuum tubing 454, which is composed of a suitable material, such asTygon tubing. The vacuum tubing 454 is in turn connected to one port ofthe vacuum inlet filter 458, which is composed of a suitable material,such as 0.1 μm diameter port microporous hydrophilic PTFE. This preventsdust, liquid droplets, or in the event of a catastrophic failure, liquidsaliva from contaminating the vacuum pump 456. The other port of theinlet filter 458 is connected to a vacuum inlet port 476 of the vacuumpump 456. In the illustrated embodiment, the vacuum pump 456 is mountedto the inside of the casing 108. Thus, the vacuum pump 456 can beoperated to create negative pressure within the sample collectionassembly 400.

[0278] Referring to FIG. 8, the fluid sensor 460, which is used to sensewhen a predetermined amount of saliva sample has been collected in thesample collection chamber 412, is mounted to a mounting flange 478,which is in turn mounted to the distribution flange 124 to place thefluid sensor 460 into contact or near contact (e.g., <0.5 mm or <0.20in) with the outside wall of the sample collection chamber 412 when thecassette 152 is fully loaded into the test console 102. In theillustrated embodiment, the fluid sensor 460 contains a 1 cm diametersense electrode that is placed at a height, such that a volume of 350 μlsaliva sample is collected at the bottom of the sample collectionchamber 412. As shown in FIG. 2, a sensor access opening 168 is providedin the rear 158 of the cassette case 154 adjacent the sample collectionchamber 412, thereby allowing the fluid sensor 460 to be in directcapacitive engagement with the sample collection chamber 412.

[0279] It should be noted that the vacuum port drive assembly 452 andvacuum pump 456 are all operated under control of a CPU 204 and I/Ocontroller 206 (FIG. 12). A vacuum motor drive sensor (generally shownin FIG. 12) and the rail 474, which is indexed, are used to provideindependent confirmation of the position of the vacuum port connector450, while vacuum pressure and air flow sensors (generally shown in FIG.12) are used to measure vacuum level and air flow rate within the vacuumpump 456.

[0280] C. Sample Collection Assembly—Operation

[0281] Having described the structure of the sample collection assembly400, its operation will now be described. After the cassette 152 isfully loaded into the test console 102, and after the hand piece 404 isplaced into the mouth of the test subject, the vacuum pump 456 issemi-automatically operated (i.e., prompted by the operator) prior toengagement of the vacuum port connector 450 with the cassette vacuumport 434. During this time, the vacuum level and flow rate are measuredusing the vacuum level and flow rate sensors to determine if they fallwithin appropriate limits (vacuum level ≧200 mmHg differential; vacuumflow rate ≧100 ml/min). This measurement ensures that the vacuum pump456 is operating properly. Simultaneous with these measurements, thevacuum port drive motor 462 is operated to move the vacuum portconnector 450 downward from its home position to its pre-collectionposition into sealing engagement with the cassette vacuum port 434. Oncethe vacuum port connector 450 is in full contact with the cassettevacuum port 434, the vacuum level and flow rate are again measured bytheir respective sensors and again determined to be within appropriatelimits (vacuum level ≧300 mmHg differential; vacuum flow rate ≧20ml/min). This measurement ensures that the cassette portion of thesample collection assembly 400 is operating properly.

[0282] If the vacuum level is less than the 300 mmHg differential, thana vacuum leak at the cassette vacuum port 434 is determined. In thiscase, the vacuum port connector 450 is disengaged and repositioned overthe vacuum port 434. The vacuum level is again measured, and if lessthan the 300 mmHg differential, the vacuum port connector 450 isdisengaged, and the chemistry cassette 152 is ejected from the testconsole 102 and then reloaded into the test console 102. The vacuumlevel is again measured, and if less than the 300 mmHg differential, thevacuum leak is considered fatal.

[0283] If the vacuum level is greater than the 300 mmHg differential,but the air flow rate is less than 20 ml/min, than a vacuum leak withinthe chemistry cassette 152 is determined, which would typically becaused by a leak within the sample/buffer mixing assembly, as will bedescribed in further detail below. In this case, the vacuum portconnector 450 is disengaged, the chemistry cassette 152 is ejected fromthe test console 102, and then, after prompting the operator, anotherchemistry cassette 152 is loaded into the test console 102. The vacuumlevel and air flow rate tests are then repeated for the new chemistrycassette 152. If on the other hand, the vacuum level is greater than the300 mmHg differential, but the air flow rate is less than 20 ml/min, itis determined that the conduit 410 or sample collection tip 406 isclogged. In this case, the vacuum port connector 450 is disengaged, thechemistry cassette 152 is ejected from the test console 102, and then,after prompting the operator, another chemistry cassette 152 is loadedinto the test console 102. The vacuum level and air flow rate tests arethen repeated for the new chemistry cassette 152.

[0284] Once the vacuum level and air flow rate have been determined tobe within the control limits, saliva collection begins. Air is drawn outof the cassette vacuum port 434, drawing a mixture of saliva sample andair into the sample collection tip 406 from the mouth of the testsubject, through the flexible conduit 410, and into the internal chamber440 of the sample collection chamber 412, where it is released from theturbulent flow conditions of the small-bore port 438 into a laminar flowwithin the much larger diameter internal chamber 440. Because the samplecollection chamber 412 is oriented in a vertical direction along theheight axis of the cassette 152, which is also held vertically by thetest console 102, gravity causes the more dense liquid saliva to settleto the bottom of the internal chamber 440, while air is drawn from thetop of the internal chamber 440 through the vacuum port 434 as a partialvacuum is applied thereto. The inverted conical shape of the internalchamber 440 facilitates collection of all of the liquid saliva from thesample collection chamber 412 as it funnels down to the small diameterdispense port 442.

[0285] Saliva collection is continued until the sample collectionchamber 412 is filled with the predetermined quantity of saliva sample,as measured by the fluid sensor 460, or until a predetermined amount oftime (in the illustrated embodiment, one minute) elapses. If one minutehas expired without collecting the predetermined amount of salivasample, the operator is prompted to readjust the sample collection tip406 within the test subject's mouth, and saliva collection commencesuntil the sample collection chamber 412 is filled with the predeterminedquantity of saliva sample, as measured by the fluid sensor 460, or untilanother predetermined amount of time (in the illustrated embodiment, oneminute) elapses. If the second minute has expired without collecting thepredetermined amount of saliva sample, the process is repeated again.Sample collection is aborted if the third attempt at collecting thesaliva fails. If, however, a predetermined quantity of saliva sample hasbeen collected, the vacuum pump 456 is turned off, and the operator,after prompted, removes the aspirator 402 from the test subject andre-caps it.

[0286] V. Sample/Buffer Mixing Subassembly

[0287] Referring to FIGS. 8 and 24-38, the system 100 further comprisesa sample/buffer mixing assembly 500, the purpose of which is to pipettepredetermined volumes of collected saliva sample and buffer solution andmix them into a less viscous and higher volume buffered saliva samplesolution. Mixing equal volumes of saliva sample and buffer also tends toequalize the pH and ionic strength of the saliva sample to minimizesudden changes during the immunoassay test that could cause the antibodyto falsely release bound antigen in the absence of the analyte.

[0288] A. Sample/Buffer Mixing Subassembly—Cassette Portion

[0289] Referring specifically to FIGS. 24-26, the portion of thesample/buffer mixing assembly 500 that resides in the cassette 152includes a buffer chamber 502, the previously described samplecollection chamber 412, and a mixing chamber 504. In the illustratedembodiment, the buffer chamber 502 and mixing chamber 504 are combinedinto a cylindrically shaped unibody design composed of a suitablematerial, such as injection molded polypropylene polymer, butalternatively can be separate and distinct bodies that are suitablymated to each other. The buffer chamber 502 and mixing chamber 504 arein axial alignment with each other, which as will be described infurther detail, facilitates interaction between plungers. The bufferchamber 502 contains a neutral buffer solution, e.g., phosphate bufferedsaline (PBS) buffer solution (pH 6.9), and the sample collection chamber412 contains saliva as a result of the sample collection process. In theillustrated embodiment, the buffer chamber 502 holds 300 μl of buffer,and as previously mentioned, the sample collection chamber 412 collects350 μl of saliva sample. Assuming equal parts of the buffer and salivasample are mixed, the mixing chamber 504 holds at least 600 μL of themixed and buffered saliva solution.

[0290] The sample collection chamber 412 is removably affixed to themixing chamber 504. Specifically, the sample dispense port 442 of thesample collection chamber 412 is mated with a sample inlet port 506 ofthe mixing chamber 504. So that an integral sample/buffer mixingassembly 500 is formed, the chamber base 432 of the sample collectionchamber 412 includes a radially extending ridge 480 (shown best in FIG.20), which mates with a slot 508 formed between two vertical radiallyextending ridges 510 on the buffer chamber 502, thus providingthree-axis rotational stability. In addition, a chamber stand 482 isformed on the exterior of the chamber base 432 of the sample collectionchamber 412, which as will be described in further detail below, restson a ledge within the cassette 152, thereby minimizing the shearing andbending stress created at the connection between the sample dispenseport 442 and the sample inlet port 506.

[0291] Referring to FIG. 27, the mixing assembly 500 further includes abuffer dispense plunger 512, which is disposed in the buffer chamber502, a sample dispense plunger 514, which is disposed within the mixingchamber 504, and buffered sample dispense plunger 516, which is alsodisposed within the mixing chamber 504. The buffer chamber 502 comprisesa cylindrical bearing surface 518 with which the buffer dispense plunger512 sealingly mates. The buffer chamber 502 comprises puncturable upperand lower seals 520 and 522 (shown in FIG. 26) at the top and bottom ofthe buffer chamber 502 to completely seal the buffer within the bufferchamber 502 until the mixing process has commenced. The upper and lowerseals 520 and 522 prevent water vapor from escaping the confines of thebuffer chamber 502 during storage of the cassette 152, and are composedof a suitable material, such as aluminum foil-lined/polymer bilayerseals. The buffer chamber 502 further includes a buffer chamber accessport 524, which provides mechanical access to the buffer chamber 502.

[0292] The mixing chamber 504 comprises a plunger bearing surface 526with which the sample dispense plunger 514 and buffered sample dispenseplunger 516 sealingly mate. The mixing chamber 504 further comprisesthree ports: (1) a buffer port 528, which facilitates the flow of bufferfrom the buffer chamber 502 into the mixing chamber 504; (2) thepreviously described sample port 506, which is mated with the dispenseport 442 of the sample collection chamber 412, and thus facilitates theflow of saliva from the sample collection chamber 412 into the mixingchamber 504; and (3) a dispense port 530, which is mated with a feedport of a flow immunoassay assembly (as will be described in furtherdetail below), and thus facilitates the flow of buffered sample solutionfrom the mixing chamber 504 into the flow immunoassay assembly. Asillustrated, the buffer port 528 is located at the top of the mixingchamber 504, the sample port 506 is located near the top of the mixingchamber 504 but below the buffer port 528, and the dispense port 530 islocated at the bottom of the mixing chamber 504. For the purposes ofthis specification, the buffer port 528 can be considered a longitudinalport, since it is parallel to the plunger bearing surface 526 of themixing chamber 504. In contrast, the sample and dispense ports 506 and530 can be considered lateral ports, since they are perpendicular to theplunger bearing surface 506 of the mixing chamber 504.

[0293] The plungers are used to dispense the buffer and sample withinthe mixing chamber 504 to form the buffered sample solution, and then todispense the buffered sample solution from the mixing chamber 504.Specifically, the movement of the buffer dispense plunger 512 within thebuffer chamber 502 towards the buffer port 528 dispenses the buffer fromthe buffer chamber 502 into the mixing chamber 504 via the buffer port528 under positive pressure. Movement of the sample dispense plunger 514within the mixing chamber 504 away from the sample port 506 dispensesthe sample from the sample collection chamber 412 into the mixingchamber 504 via the sample port 506 under negative pressure. Movement ofthe buffered sample dispense plunger 516 within the mixing chamber 504towards the dispense port 530 dispenses the buffered sample solution outof the mixing chamber 504 via the dispense port 530 under positivepressure.

[0294] The mixing assembly 500 provides for the accurate dispensing ofbuffer and saliva into the mixing chamber 504 in accordance with aselected fluid mixing ratio r, which in the illustrated embodiment, hasbeen selected to be 1:1. Specifically, the cross-sectional area A₁ ofthe buffer chamber 502, cross-sectional area A₂ of the mixing chamber,buffer dispense plunger speed S₁, and sample dispense plunger speed S₂,are selected in accordance with the equation A₂S₂=A₁S₁(1+1/_(r)). Forexample, if the buffer dispense plunger speed S₁ and sample dispenseplunger speed S₂ are equal, a 1:1 mixing ratio r can be achieved byproviding a mixing chamber cross-sectional area A₂ that is twice asgreat as the buffer chamber cross-section area A₁. On the other hand, ifmixing chamber cross-sectional area A₂ is equal to the buffer chambercross-sectional area A₁, a 1:1 mixing ratio r can be achieved byproviding a sample dispense plunger speed S₂ that is twice is great asthe buffer dispense plunger speed S₁. In either case, the greater theratio between the cross-sectional areas A₂ and A₁ or the greater theratio between the plunger speeds S₂ and S₁, the more saliva is drawninto the mixing chamber 504 relative to the buffer.

[0295] Referring to FIGS. 32-37, buffer, sample, and buffered sampledispense plungers 512, 514, and 516 will now be described. Referringspecifically to FIGS. 32 and 33, the buffer dispense plunger 512comprises a rigid plunger head 532, which includes an O-ring groove 534for seating of an O-ring (not shown). The O-ring of the buffer dispenseplunger 512 facilitates a sealing relationship between the bufferdispense plunger 512 and the bearing surface 518 of the buffer chamber502, which preferably is coated with a silicone based substance tofurther facilitate this sealing relationship. Prior to use, the bufferdispense plunger 512 is completely sealed within the buffer chamber 502between the upper and lower seals 520 and 522 As will be described infurther detail below, the buffer dispense plunger 512 can be moved downwithin the buffer chamber 502 after the top seal 520 of the bufferchamber 502 is punctured, and then down within the mixing chamber 504after the bottom seal 522 of the buffer chamber 502 is punctured.

[0296] Referring specifically to FIGS. 34 and 35, the sample dispenseplunger 514, like the buffer dispense plunger 512, comprises a rigidplunger head 536, which includes an O-ring groove 538 for seating of anO-ring (not shown). The O-ring of sample dispense plunger 514facilitates a sealing relationship between the sample dispense plunger514 and the bearing surface 526 of the mixing chamber 504, whichpreferably is coated with a silicone based substance to furtherfacilitate this sealing relationship. The sample dispense plunger 514further includes a rigid plunger body 540 and a plunger arm 542, whichincludes a 90° angled end 544. As will be described in further detailbelow, the sample dispense plunger 514 may be moved up or down withinthe mixing chamber 504.

[0297] Referring specifically to FIGS. 36 and 37, the buffered sampledispense plunger 516, like the buffer and sample dispense plungers 512and 514, also comprises a rigid plunger head 546, which includes anO-ring groove 548 for seating of an O-ring (not shown). Like with thesample dispense plunger 514, the O-ring of the buffered sample dispenseplunger 516 facilitates a sealing relationship between the bufferedsample dispense plunger 516 and the bearing surface 526 of the mixingchamber 504. The buffered sample dispense plunger 516 further includes astylus 550, which punctures the bottom seal 522 of the buffer chamber502 when seated against the buffer port 528, and a through port 552,which allows buffer from the buffer chamber 502 to flow into the mixingchamber 504. The through port 552 is of a suitable size, e.g., 1 mm. Thebuffered sample dispense plunger 516 also comprises a ferrous elementrelief 554, which temporarily stores a magnetic mixing flea (not shown).The buffered sample dispense plunger 516 is moved up or down within themixing chamber 504 with the buffer and sample dispense plungers 512 and514. The buffered sample dispense plunger 516 serves to space the sampledispense plunger 514 a distance away from the top of the mixing chamber504, so that it is adjacent to the sample port 506, the purpose of whichwill be described in further detail below.

[0298] To this end, and referring generally to FIGS. 34-37, the bufferedsample dispense plunger 516 has a top thrust surface 556, which mateswith a bottom thrust surface 558 of the buffer dispense plunger 512, anda bottom thrust surface 560, which mates with a top thrust surface 562of the sample dispense plunger 514. Specifically, the bottom thrustsurface 558 of the buffer dispense plunger 512 forms a stylus relief564, which receives the stylus 550 of the buffered sample dispenseplunger 516 in a complementary fashion, and a plug 566, which fitswithin and seals the through port 552 of the buffered sample dispenseplunger 516. The top thrust surface 562 of the sample dispense plunger514 forms a concave recess 570, which receives a convex protrusion 572of the bottom thrust surface 560 of the buffered sample dispense plunger516 in a complementary fashion. Thus, the buffer dispense plunger 512can mate with and push the buffered sample dispense plunger down withinthe mixing chamber 504 as an integral unit, and the sample dispenseplunger 514 can mate with and push the buffered sample dispense plungerup within the mixing chamber 504 as an integral unit.

[0299] B. Sample/Buffer Mixing Subassembly—Tester Portion

[0300] Referring to FIGS. 8 and 38, the portion of the sample/buffermixing assembly 500 that resides in the test console 102 comprises abuffer drive assembly 574, a sample drive assembly 576, and a mixingdrive assembly 578.

[0301] The buffer drive assembly 574 includes the previously describedlinear stepper motor 462, motor mount 464, threaded drive pin 466,threaded positioner 468, and first drive flange 470. The buffer driveassembly 574 further includes a buffer driver 580 that is mountedthrough the first flange 470. The buffer driver 580 is aligned with thebuffer chamber access port 524, so that when the buffer driver 580 isdriven downward from a pre-mix position to a dispense position, itengages and pushes the buffer dispense plunger 512 downward into thebuffer chamber 502 after the upper seal 520 of the buffer chamber 502 ispunctured. A buffer chamber access opening 170 is formed at the top 160of the cassette case 154 (shown in FIGS. 2 and 5), thereby allowing thebuffer driver 580 to engage the buffer dispense plunger 512 within thebuffer chamber 502.

[0302] The sample drive assembly 576 includes a linear stepper motor 582and a motor mount 584. The motor 582 is mounted to the motor mount 584,which is in turn mounted to the distribution flange 124. The sampledrive assembly 576 further includes a threaded drive pin 586 rotatablycoupled to the motor 582, and a threaded positioner 588 through whichthe drive pin 586 extends. The sample drive assembly 576 furtherincludes a first drive flange 590 affixed to the threaded positioner588. The first drive flange 590 includes a runner 592 that slidinglyengages the rail 476 extending along the distribution flange 124. Thesample drive assembly 576 further includes a 90° angled driver 594,which can be alternately driven upward and downward by the motor 582 apredetermined stepped distance. The angled sample driver 594 has apronged tip 596, which engages the angled end 544 of the plunger arm 542as the cassette 152 (as illustrated in FIG. 2) is loaded into the testconsole 102.

[0303] A horizontal access slot 172 is formed within the rear 158 of thecassette case 154 (shown in FIG. 2), terminating adjacent the angled end544 of the plunger arm 542 to facilitate its engagement with the prongedtip 596 of the sample driver 594. When engaged, downward and upwardmovement of the sample driver 594 correspondingly moves the sampledispense plunger 514 downward and upward into the mixing chamber 504. Avertical access slot 174 is formed within the rear 158 of the cassettecase 154 (shown in FIG. 2) adjacent the angled end 544 of the plungerarm 542, thereby allowing angled sample driver 594 to verticallydisplace the sample dispense plunger 514.

[0304] The mixing drive assembly 578 includes a rotary mixing motor 598,which is mounted to the mounting flange 478, and a mixing coupling (notshown) that is rotatably coupled to the mixing motor 598, which islocated adjacent the mixing chamber 504 of the mixing assembly 500 whenthe cassette 152 is loaded into the test console 102. The mixingcoupling contains two magnets (also not shown), which when rotated bythe mixing motor 598 magnetically interact with the ferrous element (notshown) within the mixing chamber 504.

[0305] It should be noted that the sample drive assembly 576, bufferdrive assembly 574, and mixing drive assembly 578 are all operated undercontrol of a CPU 204 and I/O controller 206 (shown in FIG. 12), withsample and buffer motor sensors (generally shown in FIG. 12) used toprovide independent confirmation of the positions of the sample andbuffer drivers 580 and 594.

[0306] C. Sample/Buffer Mixing Subassembly—Operation

[0307] Referring generally to FIGS. 27-31, with general reference toFIG. 38, the operation of the mixing assembly 500 will now be described.During operation of the mixing assembly 500, the respective sample andbuffer drive assemblies 574 and 576 are operated to move the buffer,sample, and buffered sample plungers 512, 514, and 516 upward anddownward within the chambers of the mixing assembly 500.

[0308] Referring specifically to FIG. 27, the mixing assembly 500 isshown in its shipping or home position. The buffer is completely sealedwithin the buffer chamber 502 with the top and bottom seals 520 and 522of the buffer chamber 502 yet to be punctured. The buffer dispenseplunger 512 is located at the top of the buffer chamber 502, so thatmixing chamber 504 contains the maximum amount of buffer. The bufferedsample dispense plunger 516 is at the top of the mixing chamber 504, butis not seated against the buffer port 528, and has therefore not yetpunctured the bottom seal 522 of the buffer chamber 502. The sampledispense plunger 514 is mated with the buffered sample dispense plunger516. The O-ring of the buffered sample dispense plunger 516 seals thesample port 506 in this position to ensure that there is no vacuum leakduring the previously described sample collection process.

[0309] Referring specifically to FIG. 28, the sample drive assembly 576is semi-automatically operated (i.e., prompted by the operator) to movethe sample dispense plunger 514, and thus the mated dispense plunger514, upward within the mixing chamber 504 towards the buffer port 528until the buffered sample dispense plunger 516 is seated against thebuffer port 528, thereby puncturing the bottom seal 522 of the bufferchamber 502. At this point, the thickness of the buffered sampledispense plunger 516 spaces the top thrust surface 570 of the sampledispense plunger 514 a predetermined distance from the top of the mixingchamber 504, so that it is just below the sample port 506. It should benoted that at this point time, the saliva sample has already beencollected in the sample collection chamber 412, and thus, the sampleport 506 need not be sealed at this point.

[0310] Referring specifically to FIG. 29, the buffer drive assembly 574is then automatically operated (i.e., prompted by the CPU) to engage thebuffer driver 466 with the buffer chamber access port 524, puncturingthe upper seal 520, and then moving the buffer dispense plunger 512downward within the buffer chamber 502 towards the buffer port 528.Simultaneously, the sample drive assembly 576 is operated to move thesample dispense plunger 514 downward within the mixing chamber 504towards the dispense port 530. Thus, buffer flows from the bufferchamber 502, through the buffer port 528 and then through the throughport 552 and ferrous element relief 554 of the buffered sample dispenseplunger 516, into the mixing chamber 504. At the same time, salivasample flows from the sample collection chamber 412, through the sampleport 506, into the mixing chamber 504, thereby forming a buffered samplesolution within the mixing chamber 504. During this dispensing process,the sample dispense plunger 514 remains above the dispense port 530,thus sealing it off from the buffered sample solution. It should benoted that partial mixing of the buffer and saliva sample occurs as theyare dispensed into the mixing chamber 504.

[0311] Referring specifically to FIG. 30, downward movement of thebuffer dispense plunger 512 automatically ceases after the bufferdispense plunger 512 is mated with the buffered sample dispense plunger516, and when the integral unit intersects the sample port 506 to sealit. Similarly, downward movement of the sample dispense plunger 514ceases when the sample dispense plunger 514 is located at the bottom ofthe mixing chamber 504 intersecting the dispense port 530 to seal it. Atthis point, the ferrous element (not shown) is also released from theferrous element relief 554 of the buffered sample dispense plunger 516into the mixing chamber 504. The mixing drive assembly 578 is operatedto rapidly move the ferrous element within the mixing chamber 504,thereby agitating, and thus, homogeneously mixing the buffered samplesolution. Because the sample and dispense ports 506 and 530 are bothsealed, none of the buffered sample solution leaks out the mixingchamber 504 during this enhanced mixing process.

[0312] Referring specifically to FIG. 31, the buffer drive assembly 574is automatically operated again to move the buffer dispense plunger 512,and thus the buffered sample dispense plunger 516, downward within themixing chamber 504 towards the dispense port 530. Simultaneous withthis, the sample drive assembly 576 is automatically operated to movethe sample dispense plunger 514 downward within the mixing chamber 504until the entire sample dispense plunger 514 is below the dispense port530. At this point, the dispense port 530 is exposed to the bufferedsample solution within the mixing chamber 504, and downward movement ofthe sample dispense plunger 514 automatically ceases. Downward movementof the mated buffer and buffered sample dispense plungers 512 and 516,on the other hand, continues, thereby dispensing the buffered samplesolution from the mixing chamber 504 out through the dispense port 530.Downward movement of the mated buffer and buffered sample dispenseplungers 512 and 516 continues until the buffered sample dispenseplunger 516 mates with the sample dispense plunger 514, and thus whenthe buffered sample solution has been completely dispensed from themixing chamber 504. Anytime prior to the ejection of the cassette 152from the test console 102, the sample and buffer drive assemblies 574and 576 are automatically moved back to their home positions (i.e.,disengaged from the cassette 152).

[0313] VI. Flow Immunoassay Assembly

[0314] Referring generally to FIGS. 39-65, the system 100 comprises aflow immunoassay assembly 600, the purpose of which is to generate andexhibit a measurable immunoassay reaction for each targeted drug (ten inthe illustrated embodiment) that is found in the buffered samplesolution received from the sample/buffer mixing assembly 500. Inperforming this function, the flow immunoassay assembly 600 includes asample/buffer flow assembly 602 and an immunoassay reaction assembly604. The flow immunoassay assembly 600 comprises a plurality of sampleflow channels 606 (ten in the illustrated embodiment) and a plurality ofbuffer flow channels 608 (ten in the illustrated embodiment), which arerespectively used to flow sample and buffer therethrough in effectingthe proper immunoassay reaction for each targeted drug.

[0315] A. Sample/Buffer Flow Assembly

[0316] The purpose of the sample/buffer flow assembly 602 is to provideappropriate volumes, flow rates, and flow times for continuous bufferpre-wash, sample, and buffer post-wash solutions to flow through theimmunoassay reaction assembly 604.

[0317] 1. Sample/Buffer Flow Assembly—Cassette Portion

[0318] Referring specifically to FIGS. 39 and 40, the portion of thesample/buffer flow assembly 602 that resides in the cassette 152includes a rotary valve 610 and an equal number (ten in the illustratedembodiment) of sample distribution chambers 612, buffer chambers 614,and a sample feed port 628. For purposes of context, the immunoassayreaction assembly 604, and specifically, an equal number of reactionchambers 616, a read cell assembly 618 comprising an equal number ofread cells 620, and a waste chamber 622, are also illustrated.

[0319] The rotary valve 610 includes a generally cylindrical hollowstator 624 and a generally cylindrical rotor 626, which is inserted intothe stator 624 in a rotatably sealing relationship. Preferably, thestator 624 is slightly lubricated with silicone oil to provide for asmooth rotary relationship between the stator 624 and rotor 626. Therotary valve 610 is of a suitable length to support the sample andbuffer flow channels, which in the illustrated embodiment, is 13 cm. Therotor 626 can be clocked within the stator 624 to place the rotary valve610 into a various configurations to effect predefined flow pathsbetween the afore-described mixing chamber 504 of the mixing assembly500 and the sample distribution chambers 612, between the sampledistribution chambers 612 and the immunoassay reaction chambers 616, andbetween the buffer chambers 614 and the immunoassay reaction chambers616.

[0320] In the illustrated embodiment, the rotary valve 610 can beclocked between a distribution configuration (sample distributionconfiguration), dispense configuration (sample flow configuration),first auxiliary dispense configuration (buffer pre-wash configuration),and second auxiliary dispense configuration (buffer post-washconfiguration). In the illustrated embodiment, the sample distributionand buffer pre-wash configurations are simultaneously effected byplacing the rotary valve 610 in a first position, and the sampledispense and buffer post-wash configurations are simultaneously effectedby placing the rotary valve 610 in a second position clocked 900 fromthe first position.

[0321] Specifically, the rotary valve 610, when in the sampledistribution configuration, places the sample feed port 628 in fluidcommunication with the sample distribution chambers 612, whilepreventing fluid communication between the sample distribution chambers612 and reaction chambers 616, thus facilitating distribution of thebuffered sample solution (hereinafter, sample) from the mixing assembly500 into the sample distribution chambers 612 without prematurelyexposing the immunoassay reaction chambers 616 to the sample. The rotaryvalve 610 also provides for proper venting of air displaced from thesample distribution chambers 612 during the distribution process. In theillustrated embodiment, a single vertical flow path 630 and a singlehorizontal flow path 632 accomplishes this by connecting the sample feedport 628 with the sample distribution chambers 612 using the verticalflow path 630, and connecting the sample distribution chambers 612 inseries and filling them in a cascading manner using the horizontal flowpath 632. In this manner, each of the sample distribution chambers 612are filled with precisely-measured prevolumes of sample. Another singlevertical flow path 634 connects the sample distribution chambers 612 toa vent port (not shown). It should be noted that for the purposes ofthis specification, elements are in fluid communication with each otherwhen configured such that fluid flowing through one elementcorrespondingly flows through the other element.

[0322] The rotary valve 610, when in the sample flow configuration,places the sample distribution chambers 612 in fluid communication withthe immunoassay reaction chambers 616, while preventing fluidcommunication between the sample distribution chambers 612 and samplefeed port 628, thus facilitating the flow of the sample from the sampledistribution chambers 612 through the immunoassay reaction chambers 616,and preventing the flow of the sample out through the sample feed port628. In the illustrated embodiment, ten parallel vertical flow paths 634are formed between the sample distribution chambers 612 and theimmunoassay reaction chambers 616 when the rotary valve 610 is in thesample flow configuration.

[0323] The rotary valve 610, when in either of the buffer pre-wash orbuffer post-wash configurations, places the buffer chambers 614 in fluidcommunication with the immunoassay reaction chambers 616, thusfacilitating the flow of the buffer from the buffer chambers 614 throughthe immunoassay reaction chambers 616. In the illustrated embodiment,two different sets of ten parallel vertical flow paths 636/638 areformed between the buffer chambers 614 and the immunoassay reactionchambers 616. The structure and operation of the afore-described flowpaths will be described in further detail below.

[0324] In the illustrated embodiment, the sample distributionconfiguration is clocked 0° from the buffer pre-wash configuration,i.e., the rotary valve 610 is clocked in the same position for thedistribution and buffer pre-wash configurations. Thus, the buffer can beflowed from the buffer chambers 614 through the immunoassay reactionchambers 616, and the sample can be distributed to the sampledistribution chambers 612 without clocking the rotary valve 610 betweenthe buffer dispense and sample distribution functions. Likewise, thesample flow configuration is clocked 0° from the buffer post-washconfiguration, i.e., the rotary valve 610 is clocked in the sameposition for the sample dispense and buffer post-wash configurations.Thus, the buffer can be flowed from the buffer chambers 614 through theimmunoassay reaction chambers 616, and the sample can be flowed from thesample distribution chambers 612 through the immunoassay reactionchambers 616 without clocking the rotary valve 610 between the sampledispense and buffer dispense functions. The sample flow configuration isclocked 90° from the sample distribution configuration, thus requiringmovement of the rotary valve 610 when switching from the sampledistribution function to the sample dispense function.

[0325] The sample distribution chambers 612, in combination, are sizedto contain at least an amount equal to the entire sample dispensed fromthe mixing chamber 504. For example, each of the sample distributionchambers 612 has a nominal 250 μL fluid capacity. Referring now to FIG.41, each of the sample distribution chambers 612 is cylinder-shaped andis composed of a suitable material, e.g., injection moldedpolycarbonate. The sample distribution chamber 612 comprises a plungerbearing surface 640 with which an associated sample dispense plunger 642sealingly mates. Like the previously described buffer dispense plunger512 used in the mixing assembly 500, each of the sample dispenseplungers 642 comprises a rigid plunger head 644, which includes anO-ring groove 646 for seating of an O-ring 648. The O-ring 648 of thesample dispense plunger 642 facilitates a sealing relationship betweenthe sample dispense plunger 642 and the bearing surface 640 of thesample distribution chamber 612, which preferably is coated with asilicone-based substance to further facilitate this sealingrelationship. As will be described in further detail below, movement ofthe sample dispense plunger 642 upward within the sample distributionchamber 612 flows the sample from the sample distribution chambers 612,through the associated reaction chambers 616 and read cells 620, andinto the waste chamber 622, when the rotary valve 610 is placed in thesample flow configuration.

[0326] Referring now to FIGS. 43 and 44, each of the buffer chambers 614is cylindrical-shaped and is composed of a suitable material, e.g.,injection molded polypropylene. Since the cassette 152 containsstabilized lyophilized enzyme and immunoassay reagents, as will bedescribed below, it is essential to prevent migration of water vaporthrough the walls of the buffer chambers 614. To this end, the walls ofeach buffer chambers 614 are sufficiently thick and impermeable to watervapor during the storage lifetime of the cassette 152. Each bufferchamber 614 contains a suitable neutral buffer solution, e.g., phosphatebuffered saline (PBS) buffer solution (pH 6.9) containing protein (0.2%BSA) and 0.05%_(w/v) sodium azide (NaN₃) stabilizers, and has a capacitysuitable to effectively facilitate the buffer pre- and post-washfunctions. For example, each buffer chamber 614 has a capacity of 1.0ml. Each buffer chamber 614 comprises an angled rigid tube 650, andpuncturable upper and lower seals 652 and 654 bonded at the top andbottom of the buffer chamber 614 to completely seal the buffer withinthe buffer chamber 614 until the dispensing process has commenced. Theupper and lower seals 652 and 654 prevent water vapor from escaping theconfines of the buffer chamber 614 during storage of the cassette 152,and are composed of a suitable material, such as aluminumfoil-lined/polymer bilayer seals.

[0327] Each of the buffer chambers 614 comprises a cylindrical bearingsurface 656 with which an associated buffer dispense plunger 658sealingly mates. The buffer dispense plunger 658, like the sampledispense plunger 642, comprises a rigid plunger head 660, which includesan O-ring groove 662 for seating of an O-ring 664 The O-ring 664 of thebuffer dispense plunger 658 facilitates a sealing relationship betweenthe buffer dispense plunger 658 and the bearing surface 656 of thebuffer chamber 614. The buffer dispense plunger 658 further includes astylus 666, which is configured to puncture the top seal 654 of thebuffer chamber 614. As will be described in further detail below,movement of the buffer dispense plunger 658 upward within the sampledistribution chamber 612 (after puncturing the lower seal 654), causesthe stylus 666 to puncture the upper seal 654, allowing the buffer toflow from the buffer chambers 614, through the associated reactionchambers 616 and read cells 620, and into the waste chamber 622, whenthe rotary valve 610 is placed in the buffer pre-wash or bufferpost-wash configurations.

[0328] Having already described the general function of the rotary valve610, its detailed structure will now be described. Referring to FIGS.45-51, the stator 624 is composed of a suitable material that is able toendure the large rotary torque that will be applied in order to rotatethe closely toleranced multi-channel rotor 626 therein. In theillustrated embodiment, the stator 624 is composed of aninjection-molded polycarbonate, which exhibits the required mechanicalstrength and rigidity. The stator 624 comprises a hollow cylindricalwall 668 having an inner bearing surface 670 with which the rotor 626 isrotatably associated, and an outer surface 672 with which a variety ofchamber seats and ports are associated.

[0329] Specifically, the stator 624 comprises the afore-described samplefeed port 628 (best shown in FIG. 48D), which extends through thecylindrical wall 668, and a sample feed seat 674, which extends from thecylindrical wall 668 and surrounds the sample feed port 628. The mixingchamber dispense port 530 is firmly, but removably, seated within thesample feed seat 674, thereby placing the mixing chamber 504 in fluidcommunication with the sample feed port 628. The stator 624 furthercomprises a number of distribution port pairs 676 (best shown in FIGS.47B and 49) equal to the number of sample distribution chambers 612,which in the illustrated embodiment is ten. Each of the distributionport pairs 676 includes a entry distribution port 678 and a distributionexit port 680. The distribution port pairs 676 extend through thecylindrical wall 668 and are disposed along one side of the cylindricalwall 668 in a equidistant rectilinear fashion. In the illustratedembodiment, there are no seats for the sample distribution chambers 612,but rather the distribution chambers 612 are molded directly onto theouter surface 672 of the cylindrical wall 668 over the distribution portpairs 676, thereby respectively placing the sample distribution chambers612 in fluid communication with the distribution port pairs 676. As willbe described in further detail below, the distribution port pairs 676facilitate distribution of the sample into the sample distributionchambers 612 in a cascading manner. It should be noted that thedistribution exit ports 680 are also used as sample entry dispense ports681 during sample flow, as will be described in further detail below.

[0330] The stator 624 further comprises a number of auxiliary entrydispense ports (buffer entry dispense ports) 682 (best shown in FIGS.48D and 50) and a number of corresponding auxiliary seats (bufferchamber seats) 684 equal to the number of buffer chambers 614, which inthe illustrated embodiment is ten. The buffer entry dispense ports 684extend through the cylindrical wall 668 and are disposed along anotherside of the cylindrical wall 668 in an equidistant rectilinear fashion.The buffer chamber seats 684 extend from the cylindrical wall 668 andrespectively circumscribe the corresponding buffer entry dispense ports684. The angled tubes 650 of the corresponding buffer chambers 614 arefirmly, but removably, seated within the buffer chamber seats 684,thereby placing the buffer chambers 614 in fluid communication with thebuffer entry dispense ports 684.

[0331] The stator 624 further comprises a number of exit dispense ports686 and a number of exit dispense seats (reaction chamber seats) 688(best shown in FIGS. 47B and 51) equal to the number of immunoassayreaction chambers 616. The exit dispense ports 686 extend through thecylindrical wall 668 along still another side of the cylindrical wall668 in an equidistant rectilinear fashion. The reaction chamber seats688 extend from the cylindrical wall 668 and respectively circumscribethe corresponding exit dispense ports 686. The corresponding reactionchambers 616 are firmly, but removably, seated within the reactionchamber seats 688, thereby placing the immunoassay reaction chambers 616in fluid communication with the exit dispense ports 686. Significantly,it should be noted that the exit dispense ports 686 are clocked 180°from the entry distribution ports 678 and 90° from the buffer entrydispense ports 684. It should also be noted that the last exit dispenseport 686 also serves as the previously mentioned vent port 687, as willbe described in further detail below.

[0332] Referring now to FIGS. 52-54, the rotor 626 comprises ahoneycombed rotor core 690 and a rotor lining 692 disposed on the rotorcore 690. Like the stator 624, the rotor core 690 is composed of amaterial that is able to endure the large rotary torque that will beapplied to, which in the illustrated embodiment, is injection-moldedpolycarbonate. The rotor core 690 forms a number of equidistant arcuateridges 694 and a number of longitudinal ridges 696 on which the variouschannels will be formed, as will be described in further detail below.The rotor core 690 further forms four radially equidistant sets ofalignment apertures 698 between the arcuate and longitudinal ridges 694and 696. These apertures 698 are engaged by the mandrel of the injectionmolding machine during the injection molding process. The compliantlining 692 is the portion of the rotor 626 that sealingly engages theinner bearing surface 670 of the stator 624. The compliant lining 692 iscomposed of a suitably compliant material, such as, polyurethane, whichis injection molded over the outer periphery of the rotor core 690, andspecifically, onto the various ridges formed by the honeycombedconfiguration of the rotor core 690. The end of the rotor core 690 formsfour radially extending ridges 700 for engagement with a rotary valvedrive assembly, as will be discussed in further detail below.

[0333] As will now be described, surface channels 702, surface channelstops 704, and through channels 706 associated with the rotor core 690effect the afore-described flow paths, as specified by the variousconfigurations in which the rotary valve 610 can be placed. Referringspecifically to FIG. 53A, a compliant sealing material is formed ontothe ridges of the rotor core 690. If a surface channel 702 is to beformed, the sealing material is formed on the opposing lateral surfaces708 (shown best in FIG. 54) of the ridge 694/696, while leaving theadjacent circumferential surface 710 of the ridge 694/696 exposed. If asurface channel stop 704 is to be formed, the sealing material is formedon both the lateral surfaces 708 and the adjacent circumferentialsurface 710 of the ridge 694/696. Thus, when the rotor 626 is firmlydisposed within the stator 624, fluid will flow within the surfacechannels 702 between the exposed circumferential surface of theassociated ridge and the inner bearing surface 670 of the stator 624.For the purposes of this specification, the surface channels 702associated with the arcuate ridges 694 are considered arcuate surfacechannels, and the surface channels 702 associated with the longitudinalridges 696 are considered longitudinal surface channels.

[0334] During the injection molding process, the inner surface of amandrel will be in high pressure contact with the circumferentialsurfaces 710 of the ridges 694/696 where surface channels 702 are to beformed. The inner surface of the mandrel will not be in contact at allwith the circumferential surfaces 710 of the ridges 694/696 wheresurface channel stops 704 are to be formed. For purposes of alignmentand stability, the mandrel will also be in contact with the apertures698 of the rotor core 690 between the ridges 694/696. It should be notedthat when forming surface channels 702 on the ridges of the rotor core690 via injection molding, the mandrel will preferably in high pressurecontact with the circumferential surface of the ridge opposite (i.e.,180°) that of the ridge on which the surface channel 702 is to be formedto ensure that the mandrel holds the rotor core 690 firmly in placeduring the high pressure injection molding process. Thus, unused surfacechannels 702 may be formed opposite the used surface channels as aresult of this process. It should be noted that the injection moldingprocess allows the rapid high volume assembly of a uniform leak-proofrotor 626 without the need for gaskets or O-rings.

[0335] The through channels 706 are formed transversely through thelongitudinal axis of the rotor core 690, with one end of the throughchannel 706 formed through a ridge 694/696, and the other end of thethrough channel 706 being formed through an oppositely disposed ridge694/696. A surface channel 702 is connected to a through channel 706 byforming the surface channel 702 adjacent an end of the through channel706.

[0336] Referring further to FIGS. 52 and 55-57, the rotary valve 610,when clocked in the sample distribution configuration, is channeled toplace the sample feed port 628 and distribution port pairs 676 of thestator 624 in fluid communication with each other, and thus, the sampledistribution chambers 612 in fluid communication with the sample feedport 628. The rotor 626 is also configured to place the distributionport pairs 676 in fluid communication with the vent port 687 of thestator 624, and thus the sample distribution chambers 612 in fluidcommunication with the waste chamber 622. To this end, the rotor 626comprises a feed channel 712, which connects the sample feed port 628and the first distribution port pairs 676 to each other, and a pluralityof distribution channels 714 (sample distribution channels), whichconnect the distribution port pairs 676 to each other. The rotor 626further comprises a vent channel 716, which connects the lastdistribution port pair 676 to the vent port 687.

[0337] The feed channel 712 specifically comprises a through channel706(1) and a 90° arcuate surface channel 702(1). One end of the throughchannel 706(1) connects to the sample feed port 628, and the 90° arcuatesurface channel 702(1) is connected between the other end of the throughchannel 706 and the entry distribution port 678 of the firstdistribution port pair 676. The sample distribution channels 714specifically comprise longitudinal surface channels 702(2) that connectthe distribution exit port 680 of each distribution port pair 676 withthe entry distribution port 678 of the next distribution port pair 676.The vent channel 716 includes a 90° arcuate surface channel 702(3), athrough channel 706(2), and another 90° arcuate surface channel 702(4).One end of the 90° arcuate surface channel 702(3) is connected to theexit distribution port 680 of the last distribution port pair 676, oneend of the through channel 706(2) is connected to the other end of the900 arcuate surface channel 702(3), and the other 90° arcuate surfacechannel 702(4) is connected between the other end of the through channel706(2) and the vent port 687. It should be noted that there arepreferably no channels, other than the vent channel 716, that places thesample distribution chambers 612 in fluid communication with theimmunoassay reaction chambers 616 when the rotor 626 is clocked in thesample distribution configuration, thereby preventing sample from beingprematurely dispensed from the sample distribution chambers 612 into theimmunoassay reaction chambers 616.

[0338] Referring to FIGS. 52 and 58-60, the rotary valve 610, whenclocked in the sample flow configuration, is channeled to place thesample entry dispense ports 681 (which as previously discussed coincidewith the exit distribution ports 680) and exit dispense ports 686 of thestator 624 in fluid communication with each other, and thus, the sampledistribution chambers 612 in fluid communication with the immunoassayreaction chambers 616. To this end, the rotor 626 comprises dispensechannels (sample dispense channels) 718, and specifically throughchannels 706(3), which connect the corresponding sample entry dispenseports 681 and exit dispense ports 686 with each other. It should benoted that the sample dispense channels 718 are oriented in relation tothe sample distribution channels 714 to correspond to the 90° clockingdifference between the sample distribution and sample flowconfigurations.

[0339] Referring to FIGS. 53 and 61-63, the rotary valve 610, whenclocked in the buffer pre-wash configuration, is channeled to place thebuffer entry dispense ports 684 and exit dispense ports 686 of thestator 624 in fluid communication with each other, and thus, the bufferchambers 614 in fluid communication with the immunoassay reactionchambers 616. To this end, the rotor 626 comprises first auxiliarydispense channels 720 (buffer pre-wash channels), which connect thebuffer entry dispense ports 684 and exit dispense ports 686 to eachother. Each of the buffer pre-wash channels 720 specifically comprises athrough channel 706(4) and a 90° arcuate surface channel 702(5). One endof the through channel 706 is connected to the corresponding bufferentry dispense port 682, and the 90° arcuate surface channel 702 isconnected between the other end of the through channel 706 and thecorresponding exit dispense port 686. It should be noted that the bufferpre-wash channels 720 are oriented in relation to the sampledistribution channels 714 to correspond to the 0° clocking differencebetween the buffer pre-wash configuration and the sample distributionconfiguration.

[0340] Referring to FIGS. 53, 64, and 65, the rotary valve 610, whenclocked in the buffer post-wash configuration, is channeled to place thebuffer entry dispense ports 684 and exit dispense ports 686 of thestator 624 in fluid communication with each other, and thus, the bufferchambers 614 in fluid communication with the immunoassay reactionchambers 616. To this end, the rotor 626 comprises second auxiliarydispense channels 722 (buffer post-wash channels), which connect thebuffer entry dispense ports 684 and exit dispense ports 686 to eachother. Each of the buffer post-wash channels 722 specifically comprisesthe aforementioned 90° arcuate surface channel 702(5) connected betweenthe corresponding buffer entry dispense port 682 and the correspondingexit dispense port 686. It should be noted that the buffer post-washchannels 722 are oriented in relation to the sample dispense channels718 to correspond to the 0° clocking difference between the bufferpost-wash configuration and the sample flow configuration.

[0341] 2. Sample/Buffer Flow Assembly—Tester Portion

[0342] Having just described the portion of the sample/buffer flowassembly 602 associated with the cassette 152, the portion of thesample/buffer flow assembly 602 associated with the test console 102will be discussed. Referring to FIGS. 11, 13-15, and 66-68, thesample/buffer flow assembly 602 further includes a rotary valve driveassembly 730, a number of sample drive assemblies 732, and a number ofbuffer drive assemblies 734.

[0343] Referring specifically to FIGS. 11 and 13-15, the rotary valvedrive assembly 730 functions to provide the large amount of torque (inthe illustrated embodiment, ≧5.5 N-m) necessary to clock themulti-channel rotary valve 610 90° from the sample distribution/bufferpre-wash configuration (its home position) and the sampledispense/buffer post-wash configuration (its actuated position).Specifically, the rotary valve drive assembly 730 comprises a linearstepper motor 736, and a motor mount 738 for affixing the linear motor736 to the side main base flange 122. The rotary valve drive assembly730 further includes a rotor driver 740, which is linearly displaced bythe motor 736. The rotary valve drive assembly 730 further includes acrank arm 742, one end of which is hingedly connected to the rotordriver 740, and the other end of which is affixed to a rotary pin 744.The rotary pin 744 has a pronged end 746 (best shown in FIG. 14) thatengages the end of the rotor 626 of the rotary valve 610 between theradially extending ridges 700.

[0344] The shaft of the rotary pin 744 rotatably extends through anaperture 748 formed in a pin alignment flange 750, which is suitablymounted to the top main base flange 116 to align the rotary pin 744 withthe rotor 626 of the rotary valve 610. Thus, operation of motor 736linearly translates the rotor driver 740, rotating the crank arm 742,and thus the rotary pin 744 and rotor 626.

[0345] It should be noted that the rotary valve drive assembly 730 isoperated under control of a CPU 204 and I/O controller 206 (shown inFIG. 12), with a rotary valve home sensor (generally shown in FIG. 12)used to provide independent confirmation that the end of the rotary pin744 rotationally aligns with the end of the rotor 626. It should benoted that the cassette case 154 comprises a rotary valve access opening176 (shown in FIG. 3) formed on the side of the cassette case 154adjacent one end of the rotary valve 610, thereby allowing the rotaryvalve drive assembly 730 to operably associate with the rotor 626 of therotary valve 610.

[0346] Referring specifically to FIGS. 11 and 66-68, the sample driveassemblies 732 function to move the sample dispense plungers 642 upwardwithin the respective sample distribution chambers 612. The number ofsample drive assemblies 732 may vary, but in the illustrated embodiment,is four, with (1) the first sample drive assembly 732(1) being operablyassociated with the first two sample distribution chambers 612; (2) thesecond sample drive assembly 732(2) being operably associated with thenext three sample distribution chambers 612; (3) the third sample driveassembly 732(3) being operably associated with the next three sampledistribution chambers 612; and (4) the fourth sample drive assembly732(4) being operably associated with the last two sample distributionchambers 612. The sample drive assemblies 732 are arranged in arectilinear series, so that they are properly aligned with therectilinear series of sample distribution chambers 612.

[0347] The buffer drive assemblies 734 similarly function to move thebuffer dispense plungers 658 upward within the respective bufferchambers 614. The number of sample drive assemblies 732 may vary, but inthe illustrated embodiment, equals four, with (1) the first buffer driveassembly 734(1) being operably associated with the first two bufferchambers 614; (2) the second buffer drive assembly 734(2) being operablyassociated with the next three buffer chambers 614; (3) the third bufferdrive assembly 734(3) being operably associated with the next threebuffer chambers 614; and (4) the fourth buffer drive assembly 734(4)being operably associated with the last two buffer chambers 614. Thebuffer drive assemblies 734 are arranged in a rectilinear series, sothat they are properly aligned with the rectilinear series of bufferchambers 614.

[0348] Each sample/buffer drive assembly includes a linear stepper motor752 with an associated motor driver 754, and a ganged plunger driveassembly 756. Each motor 752 is mounted to the bottom surface of thebottom main base flange 118, with the associated motor driver 754extending through a respective aperture 758 formed through the bottommain base flange 118. The motor driver 754 includes a rotational bearing(not shown) mounted thereon adjacent the top surface of the bottom mainbase flange 118 for association with the ganged plunger assembly 756.

[0349] The ganged plunger assembly 756 includes a gang base 760 with acommon aperture (not shown) formed at the bottom of the gang base 760and in which the rotational bearing of the motor driver 754 is firmlymounted. The gang base 760 further includes three equally spaced sampledispense plunger drive seats 762 disposed along the center of gang base760 opposite the common aperture 762. The ganged plunger assembly 756further includes two or three sample/buffer dispense plunger drivers 764seated within the respective plunger drive seats 762. The sample/bufferdispense plunger drivers 764 extend from the plunger drive seats 762 andup through apertures 766 formed through the top main base flange 116.For purposes of compactness, two sample/buffer dispense plunger drivers764 occupy the second and third plunger drive seats 762 with respect tothe first sample drive assembly 732(1); three sample/buffer dispenseplunger drivers 764 will occupy all three of the plunger drive seats 762with respect to the third sample drive assembly 732(2); threesample/buffer dispense plunger drivers 764 will occupy all three of theplunger drive seats 762 with respect to the third sample drive assembly732(3); and two sample/buffer dispense plunger drivers 764 will occupythe first and second plunger drive seats 762 with respect to the fourthsample drive assembly 732(4).

[0350] The sample/buffer dispense plunger driver 764 extending from thesecond (or center) plunger drive seat 762 includes a linear bearing (notshown), and the remaining sample/buffer dispense plunger drivers 764include a bushing (not shown), which are firmly mounted within theaperture 766 in the top main base flange 116. This arrangement preventsthe sample/buffer dispense plunger drivers 764 from binding within theapertures 766 of the top main base flange 116 that may otherwise occurdue to manufacturing tolerances. The apertures 766 within the top mainbase flange 116 align the sample/buffer dispense plunger drivers 764with the corresponding sample dispense plungers 642 within thedistribution chambers 612, such that operation of the respective sampleand buffer drive assemblies 732 and 734 correspondingly engage thesample dispense plungers 642 with the sample dispense plunger drivers764, and the buffer dispense plungers 658 with the buffer dispenseplunger drivers 764. It should be noted that the sample and buffer driveassemblies 732 and 734 are considered to be in their home positions whenthe ends of the respective sample/buffer dispense plunger drivers 764are below the bottom flange 118 of the cassette carriage 302, and intheir pretest positions when the ends of the respective sample/bufferdispense plunger drivers 764 are disposed through apertures 768 (shownin FIG. 13) within the bottom flange 306 of the cassette carriage 302and engaged with the respective sample and buffer dispense plungers 642and 658 within the sample distribution and buffer chambers 612 and 614.

[0351] Thus, the ganging of the plunger drivers 764 provides flexibilityin selecting different flow rates and volumes of the sample and bufferdispensed from the respective sample distribution and buffer chambers612 and 614. For example, if the accurate testing of two or three drugsrequires a relatively high volume, slow flow rate, the flow pathsassociated with these tests can be associated with a single gangassembly, while other flow paths can be associated with the other gangassemblies. It should be noted that the sample drive assemblies 732 andbuffer drive assemblies 734 are all operated under control of a CPU 204and I/O controller 206 (shown in FIG. 12). Sample and buffer motorassembly home and pre-test sensors (generally shown in FIG. 12) areprovided to ensure that the respective sample and buffer driveassemblies 732 and 734 are placed into their home and pre-test positionswhen desired. In the illustrated embodiment, a pair of printed circuitboards (PCB's) 770 (one for the set of sample drive assemblies 732 andone for the set of buffer drive assemblies 734) and correspondingindicators 734 mounted to each of the gang bases 760 are used to conveythis information.

[0352] It should also be noted that the cassette case 154 (shown inFIGS. 3 and 4) comprises for providing mechanical access to the sampleand buffer chambers 612 and 614. Specifically, a series of tendistribution chamber access openings 178 is formed on the underside of aledge 180 above the bottom 162 of the cassette case 154, therebyallowing the sample dispense plunger drivers 764 to engage the sampledispense plungers 642 within the sample distribution chambers 612.Likewise, a series of ten buffer chamber access openings 182 is formedon the bottom 162 of the cassette case 154, thereby allowing the bufferdispense plunger drivers 764 to engage the buffer dispense plungers 658within the buffer chambers 614.

[0353] B. Immunoassay Reaction Assembly

[0354] Referring generally to FIGS. 69-77, the purpose of theimmunoassay reaction assembly 604 is to: 1) perform a dynamic,continuous-flow immunoassay reaction on the sample in each of the drugchannels; (2) present the reacted sample to scanning detector; and (3)collect and permanently store fluids that have flowed within theimmunoassay reaction assembly 604. The immunoassay reaction assembly 604comprises the afore-mentioned immunoassay reaction chambers 616, readcell assembly 618, and waste chamber 622.

[0355] Referring specifically to FIGS. 69 and 70 (close up of reactionchamber) each reaction chamber 616 is configured to provide thebiochemical reaction necessary to detect analytes in the sample whenflowed therethrough. It should be first noted that although the presentinventions can employ various types of assays (e.g., direct binding,sandwich, and competition assays), the illustrated embodiment utilizesdisplacement assays to facilitate the detection of analytes in thesample. Specifically, the immunoassay reaction chambers 616 performexchange reactions between the sample and immobilized antibody proteins,which have been previously saturated with labeled antigen (and thenstabilized by lyophilization).

[0356] To this end, each immunoassay reaction chamber 616 comprises acylindrical column 774 composed of a suitable chemically insertmaterial, such as injection molded polypropylene polymer. The column 774can be of any suitable size and form that allows it to compactly fitwithin the cassette 152. In the illustrated embodiment, the column 774is 10 mm (0.4 in) in length and has a 2 mm (0.080 in) inner diameterchannel 780. The reaction chamber 616 further comprises a read cell seat775 in which ends of the read cells 620 will be seated, as will bedescribed in further detail below. Each column 774 contains dried drugreagent, and specifically, a support medium that carries lyophilizedantibody-antigen complexes that react in the presence of a target druganalyte. In the illustrated embodiment, the support medium comprisesbeads 776 that are composed of a material that is neutral to the targetdrug analytes, so that a false positive or negative signal is notcreated. Sephacryl S-1000 beads having a 60 μm median diameter have beenfound to be suitable for this purpose. Among other suitable materialsare silica or glass beads, hollow fibers, and activated polymers. Infurther embodiments, the hollow fibers or bundles of capillary tubes mayserve simultaneously as the reaction chamber 616 and support medium.

[0357] The antibody-antigen complexes are formed by covalently bondingimmobilized antibodies on the beads 776 for the appropriate drug to betested. In the illustrated embodiment, approximately 10% of the activesurface of each bead is covered with the antibody. The immobilizedantibody is then saturated with labeled antigen, which form the drugtracer. Any suitable labeled antigen (such as, e.g., radiolabels,fluorophores, chromophores, electroactive groups, and electron spinlabel) can be used in the process, but in the illustrated embodiment,the labeled antigen comprises covalently bonded fluorescent CY5 dye,which excites best at 650 nm and fluoresces at 655-700 nm. Thetracer-saturated antibody beads are stabilized with protein (BSA) andtrehalose, and then packed as a known volume slurry into the column 774.The column 774 is washed to remove any excess labeled dye, and thenlyophilized to provide for stability of one year under appropriatestorage conditions. In the illustrated embodiment, each column 774contains 3 mg of dried reagent. Further details on preparing lyophilizedantibody-antigen complexes are disclosed in U.S. Pat. No. 5,354,654,entitled “Lyophilized Ligand-Receptor Complexes for Assays and Sensors,”which is fully and expressly incorporated herein by reference.

[0358] In order to contain the beads 776, while allowing the flow ofliquid through the reaction chamber 616, circular-shaped porous barriersor screens (frits) 778 are provided at the bottom and top of the columnchannel 780. The frits 778 also serve to prepare the sample by filteringout all particles larger than the pore size (in the illustratedembodiment, 30 μm) from the saliva. It is noted that larger particles(e.g., 135 μm) are initially filtered by the sample collection tip 406of the previously described sample collection assembly 400. In thepreferred embodiment, the frits 778 are advantageously self-sealing inthat they are held in place by interference fit within the columnchannel 780.

[0359] With reference to FIG. 71, a preferred method of manufacturingthe immunoassay reaction chamber 616 using a frit tool assembly 850 willnow be discussed. The frit tool assembly 850 is capable ofsimultaneously manufacturing, compressing, and installing frits 778within a plurality reaction columns 774, which in the illustratedembodiment, is accomplished for an 12×96 array of immunoassay reactionchambers 616. The compressed frits 778 when disposed within the column774 are allowed to expand, thereby creating compressive forces betweenthe first and the column channel 780. For purposes of clarification andbrevity, the manufacture of only one immunoassay reaction chamber 616will be discussed in detail.

[0360] The frit tool assembly 850 generally comprises a punch plate 852,stripper plate 854, die plate 856, frit compression plate 858, chamberadapter plate 860, and base plate 861. The punch plate 852 includes anumber of cylindrical punch plate pins 855 extending therefrom. Thestripper plate 854 includes an equal number of circular passages 862passing therethrough. Likewise, the die plate 856 includes an equalnumber of circular shearing passages 864 passing therethrough. Disposedbetween the stripper and die plates 854 and 856 is a frit material 866.As illustrated in FIG. 72, a motor assembly (not shown) operably coupledto the punch plate 852 is configured to drive the punch pins 855 (eachof which has a diameter equal to the diameter of the die plate shearingpassages 862) through the strip plate passages 862 and into the dieplate shearing passages 864 to shear off the frits 778 within the dieplate shearing passages 864. It is noted that the diameter of theuncompressed frit 778 will be approximately equal to the diameter of thedie plate shearing passages 864, which in the illustrated embodiment, is0.082 in.

[0361] The frit compressing plate 858 includes an equal number ofconical passages 868 passing therethrough. The conical passages 868 haveupper openings 870, which are configured to receive the newly cut frits778 from the die plate shearing passages 864. In the illustratedembodiment, the diameters of the upper openings 870 are greater thanthat of the die plate shearing passages 864 to compensate formanufacturing and alignment tolerances, thereby ensuring that the upperopenings 870 can receive the frits 778 from the die plate shearingpassages 864. In the illustrated embodiment, the upper openings 870 havediameters of 0.084 in. The conical passages 868 naturally taper to loweropenings 872, the diameters of which are less than that of theuncompressed frit 778 and column channel 780. In the illustratedembodiment, the diameters of the lower openings 872 are 0.074 in, whichare less than the 0.082 in. diameters of the uncompressed frits and0.080 in. diameters of the column channels 780. Thus, as illustrated inFIG. 73, when the punch pins 855 are further driven down into theconical passages 868 of the frit compression plate 858, the frits 778are pushed through the conical passages 868, where they are laterallycompressed by the lower openings 872.

[0362] The frit compression plate 858 further includes an equal numberof male portions 874 in which the conical passages 868 terminate. Thechamber adapter 860 includes an equal number of corresponding femaleportions 876, which are configured to be received by the male portions874 of the frit compression plate 858. The chamber adapter 860 furtherincludes an equal number of cylindrical passages 878, which terminateadjacent the lower openings 872 of the frit compression plate 858. Thecylindrical passages 878 are sized to firmly receive the columns 774,such that the ends of the columns 774 abut the lower passages 780 of thefrit compression flange 858 when mounted therein. Thus, as illustratedin FIG. 74, when the punch pins 855 are further driven down through thecylindrical passages 878 of the chamber adapter 860, the compressedfrits 778 are pushed into the column channels 780, where they expandsinto compression with the column channel 780 to form an interferencefit.

[0363] The punch plate pins 855 are then pulled out of the chamberadapter 860, frit compression plate 858, die plate 856, and stripperplate 854, with the stripper plate 854 functioning to hold the fritmaterial 866 in place as the punch plate pins 855 are pulled from thefrit material 866. The columns 774 are then suitably flipped upside downand filled with the reagent. The afore-described process is thenrepeated to interference fit other frits 778 within the opposite ends ofthe columns 774 to form complete immunoassay reaction chambers 616, withthe exception that the frit material is preferably displaced apredetermine distance to move unused frit material 866 over the shearingpassages 864 of the die plate 856.

[0364] Referring now to FIGS. 75-77, the read cell assembly 618 isconfigured to present the reacted sample to a light source, where anylabeled antigen will be exited into fluorescent emission, the intensityof which can be measured by a suitable detector. The read cell assembly618 is molded from a single piece of transparent, e.g., injectionmolded, bubble-free, acrylic polymer, which includes vertical andhorizontal disposed flanges 782 and 784.

[0365] The vertical flange 782 of the read cell assembly 618 forms thenumber of optical read cells 620 with internal lumens 786 (which in theillustrated embodiment, equals ten). The transparent material isselected to have especially low endogenous fluorescence (e.g., λexc=636nm, λem=670 em) and no UV inhibitors or plasticizers as additives. Inthe illustrated embodiment, each of the molded read cells 620 isrectangular parallel-piped in shape, and has a width, depth, and lengthequal to 2.0 mm, 2.0 mm, and 10 mm, respectively. The read cell lumen786 is cylindrically-shaped and has diameter of 1.0 mm. Each of theoptical read cells 620 includes an input port 788 configured to beinserted into the read cell seat 775 of the corresponding reactionchamber 616. Each of the optical read cells 620 comprises an energytransmission port 790 located opposite the input port 788, which as willbe described in further detail below, is used to transmit opticalenergy, and specifically laser energy, through the read cell lumen 786.

[0366] The horizontal flange 784 of the read cell assembly 618 forms anumber of drain channels 792 (ten in the illustrated embodiment), whichare in fluid communication with the optical read cells 620, and a singlecommon drain channel 794, which is fluid communication with the drainchannels 792. This common drain channel 794 is further in fluidcommunication with two outlet drain ports 796 that exit out the bottomof the horizontal flange 784 into the waste chamber 622.

[0367] The fluorescent labeled antigens are excited by transmittinglaser energy down the longitudinal axis of the read cell lumen 786 usinga light source, and specifically a laser, thereby exciting any labeledantigen into fluorescence. Thus, the laser beam enters the optical readcell 620 through the energy transmission port 790 and penetrates downthe longitudinal axis of the read cell lumen 786, illuminating thesample stream, as well as the wall of the read cell lumen 786, with thelaser light. The fluorescent emission within the optical read cell 620is then detected by a detector, the intensity of which is indicative ofthe quantity of the target drug analyte within the sample, therebyallowing the sample to be quantitatively analyzed. It should be notedthat the transmission of laser energy down the longitudinal axis of theoptical read cell 620, as opposed to perpendicular to the longitudinalaxis of the cell 620, allows the detector to view a greater quantity ofthe labeled antigen at one time, thereby increasing the accuracy of themeasurement and subsequent analysis of the sample.

[0368] In order to quantitate low-intensity fluorescent photons withinthe labeled antigen, stray light must be eliminated from the cassette152. The test console 102, which surrounds the cassette 152, providesthe first level of stray light protection and removes 99% of ambientlight. Each optical read cell 620 is masked by an optical read slit 184formed on the front 156 of the cassette case 154 (shown in FIGS. 3-5).In the illustrated embodiment, this slit 184 is 1.2 mm in width and 10mm in length. The end of each optical read cell 620 is also masked by anoptical excitation aperture 186 formed on the top 160 of the cassettecase 154 (shown in FIGS. 3 and 5). The cassette case 154 is alsomanufactured from light-absorbing dark pigmented plastic, and togetherwith the optical read slits 184 and optical excitation apertures 186,eliminates 99% of the remaining stray ambient light from the exteriorenvironment. No exposed source of red light, such as red-colored lightemitting diodes (LEDs), are contained within the test console 102. Atthe top and sides of the optical read cell 620, a highly light-absorbentblack plastic light shield 798 with interior baffles is used to absorbas much of the scattered light beam and unwanted fluorescent light aspossible. Only multiple reflections from black and dark surfaces of thelight shield and cassette case 154 can cause stray light. Thus, theundesirable channel-to-channel stray light pickup is minimized.

[0369] The waste chamber 622 is configured to collect and permanentlystore the buffer- and saliva-containing sample fluids, so that theycannot leak from the confines of the cassette case 154. The cassette 152can then be disposed of simply as solid waste without hazard fromleakage of potentially biologically hazardous saliva samples. The wastechamber 622 is composed of a suitable leak proof material, such as blackpolycarbonate, and is configured to be nested within the angled readcell assembly 618. The waste chamber 622 includes a pair of drain inletports 799 that positionally correspond with, and are configured toreceive, the drain outlet ports 796 of the read cell assembly 618. Thewaste chamber 622 includes a self-sealing vent port (not shown) withinwhich there is tightly disposed a hydrophobic seal (not shown). In theillustrated embodiment, the seal is composed of a self-sealingpolyethylene membrane that comprises small-diameter pores (e.g., 25 μmdiameter) that are coated with a hydrophilic substance, such ascarboxymethlcellulose. When wetted, the hydrophilic pores rapidly swell,closing the pore interiors, thereby preventing liquid from passingthrough the membrane. This self-sealing vent port, thus facilitatespassing air, while preventing the biologically hazardous saliva fromleaking out of the cassette 152 after its disposal following use.Further, the buffer dispensed during buffer pre- and post-wash contain a0.05% solution of sodium azide (NaN3) antibacterial preservative toprevent the growth of bacteria in the fluid medium.

[0370] C. Flow Immunoassay Assembly—Operation

[0371] Having described the detail structure of the flow immunoassayassembly 600, its detailed operation will now be described. When thecassette 152 is loaded into the test console 102, the recess formedwithin the end of the rotary pin 744 engages the ridged end of the rotor626 of the rotary valve 610 (FIG. 38). Additionally, the sample andbuffer drive assemblies 734 and 736 (FIG. 66) are automatically (i.e.,prompted by the CPU) moved from their home positions to their pre-testpositions, such that the sample dispense plunger drivers 764 are engagedwith the respective sample dispense plungers 642 (FIG. 78), and thebuffer dispense plunger drivers 764 are engaged with the respectivebuffer dispense plungers 658 (FIG. 79). For purposes of brevity, onlyone sample dispense plunger 642 and one buffer dispense plunger 658 isshown engaged with the respective plunger drivers 764.

[0372] Turning to FIGS. 55, 56, and 78, the sample distribution isperformed in order to fill the sample distribution chambers 612 prior toflowing the sample through the immunoassay reaction chambers 616.Specifically, the rotary valve 610 is first placed into the sampledistribution configuration, and the sample is pumped from the dispenseport 530 of the mixing assembly 500 into the sample feed port 628, whichas previously described, is accomplished by operating the buffer driveassembly 574 associated with the buffered sample dispense plunger 516 ofthe mixing assembly 500. It should be noted that the rotary valve 610 ispreferably manufactured and stored in the sample distribution/bufferpre-wash configuration, in which case, the rotary valve drive assembly730 need not be operated to clock the rotor 626 prior to the sampledistribution process.

[0373] It should also be noted that, during the manufacturing process,the sample dispense plungers 642 are preferably pushed all the way tothe top of those sample distribution chambers 612 (blanked out) thatwill not be used. For example, if the five drugs-of-abuse are to betested, the remaining five sample distribution chambers 612 will beblanked out. In the illustrated embodiment, distribution chambers 2-3,6, 8, and 10 are shown blanked out. In this manner, the sample is notdistributed into unused sample distribution chambers 612, and thuswasted. To allow the sample to traverse across blanked out sampledistribution chambers 612, a divot (not shown) is preferably made in thetop of each sample dispense plunger 642 to ensure fluid communicationbetween the entry and exit ports 678 and 680 of the distribution portpair 676 associated with any blanked out sample distribution chamber612. In the case where a sample distribution chamber 612 need not becompletely filled, the corresponding sample dispense plunger 642 can bepushed up into the sample distribution chamber 612 a predefined distanceas dictated by the amount of sample that will be dispensed from thesample distribution chamber 612. In the illustrated embodiment, thesample dispense plungers 642 are shown displaced a predetermineddistance from the bottoms of the distribution chambers 5 and 9.

[0374] Optionally, the sample drive assemblies 732 associated with thesample distribution chambers 612 to be blanked out or partially filledare operated under control of the CPU 204 and I/O controller 206 (FIG.12) to push the sample dispense plungers 642 up into those sampledistribution chambers 612 the required distance, such that the amount ofsample distributed into each sample distribution chamber 612 isperformed in accordance with a quantity of sample required for thecorresponding sample flow channel, if any. This information can bederived from the barcode affixed to the chemistry cassette 152. If thesample drive assemblies 732 are operated to adjust the sample dispenseplungers 642, it is preferable that those sample distribution chambers612 that are to be filled with the same quantity of sample should beassociated with the same sample drive assembly 576.

[0375] During sample distribution, the sample flows from sample feedport 628, through the feed channel 712 and into the first distributionchamber 612 via the entry distribution port 678 of first distributionport pair 676. Once the first distribution chamber 612 fills up, thesample flows out through the exit distribution port 680, through thesample distribution channel 714, and into the next availabledistribution chamber 612 via the entry distribution port 678 of the nextdistribution port pair 676. This cascading process continues until thelast available distribution chamber 612 is filled with the sample. FIG.78 illustrates that distribution chamber 7 is currently being filled,with distribution chambers 1, 4, and 5 having already been filled, anddistribution chambers 2, 3, and 6 being blanked out. During the sampledistribution process, air is vented from the sample distributionchambers 612. Specifically, as the sample distribution chambers 612 arebeing filled with the sample, the remaining air with each distributionchamber 612 is forced out through the corresponding exit distributionport 680, through the sample distribution channel 714 and into the nextavailable distribution chamber 612 via the next entry distribution port678. The air within the last available distribution chamber 612 isforced out the exit distribution port 680, through the vent channel 716,through the corresponding reaction chamber 616 and read cell 620, andinto the waste chamber 622. As illustrated, since distribution chamber 7is currently being filled and distribution chambers 8 and 10 are blankedout, air (dashed line) escapes from the exit distribution port 680 ofdistribution chamber 7, into and out of the entry distribution port pair676 of distribution chamber 9, and out through the vent channel 716.

[0376] Referring to FIGS. 61-63 and 79, buffer pre-wash is performed to(1) rehydrate the immobilized antibody proteins, thereby conditioningthe stabilized lyophilized column to be ready to accept liquid sampleand kinetically release labeled antigen for each of the assays inresponse to the presence of any drug molecules in the sample; (2) washaway non-specifically bound labeled antigen and other unwanted molecules(such as trehalose stabilizing agent); (3) pre-equilibrates the columnwith buffer of the appropriate pH and ionic strength in preparation forthe sample; and (4) provides a convenient means to calibrate thefluorescent read out from the read cell assembly 618. It should be notedthat the buffer pre-wash can be performed at any time in relation to thesample distribution process, but preferably is accomplished prior to thesample dispensing process.

[0377] At the beginning of the buffer pre-wash, the rotary valve 610 isplaced into the buffer pre-wash configuration, which in the illustratedembodiment, is the same as the sample distribution configuration. Thus,the distribution and buffer pre-wash can be conveniently accomplishedsimultaneously, or at the least, the rotary valve 610 need not berotated between sample distribution and buffer pre-wash. In any event,the buffer drive assemblies 734 are automatically operated, placing thebuffer dispense plunger drivers 764 into contact with the bufferdispense plungers 658 after puncturing the bottom seals 654, andthereafter pushing the buffer dispense plungers 658 up within the bufferchambers 614, puncturing the top seals 652 with the styluses 666. Thebuffer is dispensed out of the buffer chambers 614, through the rigidtubes 650, buffer entry dispense ports 684, buffer pre-wash channels720, and exit dispense ports 686. The buffer then flows through andconditions the immunoassay reaction chambers 616, where theafore-described pre-conditioning takes place, through the optical readcells 620, where the buffer is exposed to laser light and itscorresponding fluorescence is measured to calibrate the read out, andthen finally into the waste chamber 622, where the buffer is permanentlystored.

[0378] The flow of buffer through the immunoassay reaction chambers 616is of a suitable flow rate and volume. For example, for thedrugs-of-abuse, a buffer pre-wash using a buffer volume of 400 μl at aflow rate of 400 μl/min has been found to be suitable. In this case, itwill take 60 seconds to complete the buffer pre-wash.

[0379] Turning to FIGS. 58-60 and 80, the sample flow is performed inorder to flow the sample through the immunoassay reaction chambers 616.The purpose of the sample flow is to expose the immunoassay reactionchambers 616 to any drug present within the sample. Thus, the sample,which may contain drug-of-abuse molecules, flows past the bound,antibody-antigen complex, causing an exchange reaction between thelabeled antigen and the unbound drug molecules. Since the native drugantigen molecules bind more tightly to their corresponding antibodymolecules, than the more bulky labeled antigen molecules, the reactionchamber 616 preferentially exchanges the labeled antigen with the realdrug-of-abuse molecules. The net result is an increase in theconcentration of fluorescent labeled antigen.

[0380] Specifically, the rotary valve 610 is automatically clocked 90°from the sample distribution configuration (buffer pre-washconfiguration) into the sample flow configuration (buffer post-washconfiguration). The sample drive assembly 734 is automatically operated,pushing the sample dispense plungers 642 up within the sampledistribution chambers 612. The sample is dispensed out of the sampledistribution chambers 612, through the sample entry dispense ports 681(which are the same as the exit distribution ports 680), dispensechannels 718, and exit dispense ports 686. The sample then flows throughthe immunoassay reaction chambers 616, where the exchange immunoassayreaction occurs, through the optical read cells 620, where the sample isexposed to laser light and its corresponding fluorescence is measured,and then finally into the waste chamber 622, where the sample ispermanently stored. The sample flow is performed until the entirety ofthe sample has been emptied from the sample distribution chambers 612.It should be noted that the construction of the rotary valve 610 allowsthe sample to be injected as a contiguous band into the buffer flow,i.e., it prevents, or at least minimizes, the amount of air introducedinto the flow that may otherwise be caused by the operation of atraditional valve between the buffer pre-wash and sample dispenseprocesses.

[0381] The flow of the sample through the immunoassay reaction chambers616 is of a suitable flow rate and volume. For example, a flow rate of100 μl/min for all of the drug-of-abuse, and sample volumes of 50 μl, 50μl, 100 μl, 250 μl, and 50 μl for cocaine, opiates (heroin, morphine,and codeine), phencyclidine (PCP), amphetamines/methamphetamines, andmarijuana (tetrahydrocannabinol or THC), respectively, has been found tobe suitable. Thus, in this case, it will take about 2½ minutes tocomplete the sample dispense process. It is noted that the sampledistribution chambers 612 corresponding to the 50 μl and 100 μl samplevolumes will be partially filled, in which case, the sample dispenseplungers 642 will have been pushed up within these sample distributionchambers 612 either during the manufacturing process or by operation ofthe corresponding drive assemblies 734 and 736. For example, assuming a250 μl capacity, a sample dispense plunger 642 will be pushed up ⅘ ofthe way for a sample distribution chamber 612 that will be partiallyfilled with 50 μl of sample and ⅗ of the way for a sample distributionchamber 612 that will be partially filled with 100 μl of sample.Optionally, the sample drive assemblies 732 can be operated undercontrol of the CPU 204 and I/O controller 206 (FIG. 12) to move thesample dispense plungers 642 at different speeds, thus effectingdifferent flow rates for the sample flow channels. The information onthe desired flow rates for the sample flow channels can be derived fromthe barcode affixed to the chemistry cassette 152.

[0382] Referring to FIGS. 64, 65, and 81, the buffer post-wash isperformed to push the remaining sample through the immunoassay reactionchambers 616 and read cells 620. Specifically, the rotary valve 610 isplaced into the buffer post-wash configuration, which in the illustratedembodiment, is the same as the sample flow configuration. The bufferdrive assemblies 734 are automatically operated again, further pushingthe buffer dispense plungers 658 up within the buffer chambers 614. Theremaining buffer is dispensed out of the buffer chambers 614, throughthe rigid tubes 650, buffer entry dispense ports 684, buffer post-washchannels 722, exit dispense ports 686, reaction chambers 616, read cells620, and finally into the waste chamber 622. This is performed until theentirety of the buffer has been dispensed from the buffer chambers 614.The volume of the buffer chambers 614, and the speed of the bufferdispense plungers 658, are such that buffer continues to flow throughthe immunoassay reaction chambers 616 even after the sample is no longerflowing. In this manner, the buffer will push any remaining sampleresiding in the rotary valve 610 out through the immunoassay reactionchambers 616 and read cells 620, providing for a more efficient use ofthe sample.

[0383] The flow of the buffer through the immunoassay reaction chambers616 are of a suitable flow rate and volume. For example, a flow rate of100 μL/min and 250 μL volume for all of the drug-of-abuse has beendetermined to be suitable. Thus, in this case, it will take about 2½minutes to complete the buffer post-wash.

[0384] Prior to the ejection of the cassette 152 from the test console102, automatic operation of the sample drive assemblies 732 move thesample dispense plunger drivers 764 downward, disengaging them from thesample distribution chambers 612 and cassette carriage 302 until theyare back in their home positions. Likewise, automatic operation of thebuffer drive assemblies 734 moves the buffer dispense plunger drivers764 downward, disengaging them from the buffer chambers 614 and cassettecarriage 302 until they are back in their home positions.

[0385] VII. Optical Flow Immunoassay Scanning Assembly

[0386] Referring generally to FIGS. 13, and 82-88, the system 100comprises an optical flow immunoassay scanning assembly 900, the purposeof which is to measure the amount of labeled antigen, and specificallyfluorescent CY5 dye, flowing through each of the optical read cells 620.In performing this function, the optical flow immunoassay assembly 600includes a dynamic scanning assembly 902, an optical excitation assembly904, and an optical detection assembly 906.

[0387] A. Dynamic Scanning Assembly

[0388] The purpose of the dynamic scanning assembly 902 is to translatethe positions of the optical excitation assembly 904 and opticaldetection assembly 906, so that they can interact with the optical readcells 620 of the flow immunoassay assembly 600. To this end, the dynamicscanning assembly 902 comprises a vertically extending rigid mechanicalbench 908 mounted to the top flange 116 of the main base 114. Thedynamic scanning assembly 902 further includes a scanner head mechanism910 that rides on top of the mechanical bench 908. Specifically, thedynamic scanning assembly 902 includes a runner 912, which is mounted tothe scanner head mechanism 910, and a rail 914, which is mounted to thetop of the mechanical bench 908. Thus, the runner 912 rides on the rail914, such that the scanner head mechanism 910 rides smoothly along thetop of the mechanical bench 908.

[0389] The scanner head mechanism 910 includes a horizontal flange 916and a vertical flange 918 for mounting various components. Specifically,the horizontal flange 916 extends along the top of the chemistrycassette 152 when loaded into the test console 102, and includes a laseraperture 918 (shown best in FIG. 13) with which the optical excitationassembly 904 is associated to interact with the optical read cells 620.The horizontal flange 916 is used to mount a position sensor 920, whichas will be described in further detail below, aids in determining thelocation of the scanner head mechanism 910 in relation to each opticalread cell 620. In addition, the previously described runner 912 ismounted to the vertical flange 918. The vertical flange 918 extendsalong the front of the chemistry cassette 152 when loaded into the testconsole 102 and includes a detector aperture 922 with which the opticaldetection assembly 906 is associated to interact with the optical readcells 620. The vertical flange 918 comprises a sensor actuator 924(shown best in FIG. 13), which as will be described below, aid indetermining the extreme limits of the scanner head mechanism 910 inrelation to the mechanical bench 908.

[0390] The dynamic scanning assembly 902 further includes a scanningdrive assembly 926, which automatically scans the scanner head mechanism910 in relation to the mechanical bench 908, and thus, the loadedcassette 152. The scanning drive assembly 926 includes a rotationalstepper motor 928 and a motor mount 930, which affixed the motor 928 tothe mechanical bench 908. The scanning drive assembly 926 furtherincludes a driver pulley 932, which is rotatably mounted to the motor928, and an idler pulley 934, which is rotatably mounted to the front ofthe mechanical bench 908. The scanning drive assembly 926 furtherincludes a circular, notched drive belt (not shown) mounted around therespective driver and idler pulleys 932 and 934. The scanner headmechanism 910 is affixed to the drive belt, such that operation of themotor 928 moves the drive belt, thus linearly translating the scannerhead mechanism 910 in relation to the mechanical bench 908, which lineartranslation is ensured by the rail and runner arrangement.

[0391] It should be noted that one scan cycle of the dynamic scanningassembly 902 consists of one scan in the forward direction(left-to-right, referred to simply as the “forward scan”) immediatelyfollowed by one scan in the reverse direction (right-to-left, referredto simply as the “reverse scan”). To ensure that the scanner headmechanism 910 does not translate to far, the scanning drive assembly 926includes a scanner home position sensor 936, which is mounted to one endof the mechanical bench 908, and a scanner end position sensor 938,which is mounted to the other end of the mechanical bench 908, toindependently indicate the position of the scanner head mechanism 910near the extreme limits of travel during each scan cycle. The sensoractuator 924 mounted to the vertical flange 918 of the scanner headmechanism 910 triggers the scanner home and end position sensors 936 and938 to facilitate this determination. The forward and reverse scans ofthe scanner head mechanism 910 are performed under control of the CPU204 (FIG. 12). Specifically, the CPU 204 generates instructions used toprogram the I/O controller 206 for the motor 928, which in theillustrated embodiment, is performed at a linear rate of 20 cm/s, thusperforming a single scan of all ten channels in one second (1 s).

[0392] To indicate the location of the optical read cells 620, thescanning drive assembly 926 further includes an indexed flange 940,which is mounted to the front of the mechanical bench 908, and theposition sensor 922, which, as previously described, is mounted to thehorizontal flange 916 of the scanner head mechanism 910. To this end,the indexed flange 940 comprises notches 942 (ten, in the illustratedembodiment) that are spaced apart the same distance in which the opticalread cells 620 are spaced apart, i.e., each notch 942 spaced from anadjacent notch 942 a distance equal to the distance in which eachoptical read cell 620 is spaced from an adjacent read cell 620. Thus,when the position sensor 922 associated with the scanner head mechanism910 senses a notch 942 within indexed flange 940, a certain portion ofthe scanner head mechanism 910 will be aligned with a read cell 620,which as will be described in further detail below, indicates that theoptical read cell 620 is currently being scanned.

[0393] B. Optical Excitation Assembly

[0394] The purpose of the optical excitation assembly 904 is to provideconstant wavelength, constant intensity light to the optical read cells620, so that each of the labeled antigen, and specifically fluorescentCY5 dye, flowing therethrough are excited by photons of the correctwavelength. To this end, the optical excitation assembly 904 comprises alaser module 944 (best shown in FIG. 13), which is mounted within thelaser aperture 918 formed through the horizontal flange 916 of thescanner head mechanism 910. The optical excitation assembly 904 furtherincludes a heat sink 946 and fan 948, which provide heatsinkingfunctionality to the optical excitation assembly 904.

[0395] As illustrated in FIG. 86, the laser module 944 includes amodular housing 950, which contains a laser source 952 and athermocontroller 954 that are configured to provide constant outputcontrolled laser energy to the optical read cells 620. The laser source952 is rigidly mounted within the modular housing 950, which aligns thelaser source 952 with the optical transmission port 790 of the read cell620. Thus, the laser source 952 transmits laser energy through theoptical transmission port 790 of each read cell 620, and through thecorresponding lumen 786.

[0396] In the illustrated embodiment, the laser source 952 is mounted,such that the resultant laser beam 956 intersects the longitudinal axis958 of the read cell lumen 786 at an oblique entry angle. If thisoblique angle is, e.g., 45° a two times (2×) overscan of each opticalread cell 620 in the vertical axis (and many times overscan in thehorizontal axis due to the linear translation of the scanner headmechanism 910) is provided. This assures that some portion of thecross-section of the laser beam 956 intersects the transmission ports790 of the read cell lumens 786, even if some displacement of theoptical read cells 620 along the length of the cassette 152 exists,e.g., if the cassette 152 is slightly warped, or otherwise due tomanufacturing tolerances in the injection molded plastic read cellassembly 618. The laser source 952 specifically comprises a 5 mWsolid-state laser diode that nominally operates at 636 nm and has aresultant laser beam 956 with a 2 mm×4 mm rectangular beam profile.

[0397] Thus, operation of the dynamic scanning assembly 902,mechanically scans the resultant laser beam across each optical readcell 620 through the transmission port 790 and down the longitudinalaxis of the lumen 786, thereby illuminating the sample stream, as wellas the walls of the optical read cells 620, with laser light. Thus, at alinear scan rate of 20 cm/s, some portion of each 2 mm wide optical readcell 620 will be exposed to the laser beam for approximately 0.020 s.

[0398] The thermocontroller 950 controls the temperature of the heatsink 946, thereby controlling the operating wavelength of the lasersource 948. The thermocontroller 950 is a 4W Peltier thermocontroller,which ensures that the output wavelength of the laser source 948 ismaintained substantially constant. The optical excitation assembly 904further includes a laser controller 960 to control the operating currentof the laser source 948. The laser controller 960 comprises an internalreference optical diode (not shown) that samples a small portion of thelaser output and provides a reference voltage that is input to the lasercontroller 960 and used to control the current to the laser source 948as a feedback signal from an amplifier (not shown) in the lasercontroller 960.

[0399] The optical excitation assembly 904 further comprises a laserfilter 962, which is mounted between the laser source 948 and theoptical read cell 620 to provide adequate rejection of scattered lightproduced by the turbid saliva samples (turbidity of human saliva samplescan vary by as much as 20-to-1) and by the read cell assembly 618. Sincesolid-state laser diodes typically contain a light emitting diode (LED)with a high-Q resonant cavity, the LED produces a relatively lowintensity broad band of radiation approximately 200 nm in width on whichis superimposed a high intensity, narrow band (≅1 nm) of resonant laserenergy. For example, the laser energy can be about 10⁶ (a million times,or 6 orders of magnitude) more intense than the low energy broadbandradiation. Consequently, the low energy broadband radiation of asolid-state laser diode is typically ignored. Since fluorescence,however, is 10⁴-10⁵ times less intense than scattering due to the lowefficiency of the fluorescent radiation process, scattered light outsidethe nominal laser wavelength that reaches the laser source 948 from thesample can be even more intense than the fluorescent light generatedwithin each optical read cell 620.

[0400] Thus, in order to eliminate significant error due to lightscattering by the sample, and thereby ensure that detected light is dueto the fluorescence of CY5 dye found within the optical read cell 620,rather than to high turbidity of the saliva sample, scattered light mustbe highly rejected from the optical detection assembly 906. To this end,the laser filter 962 comprises a 636 nm±5 nm FWHM (full width at halfmaximum height) bandpass filter with steep rolloff (20 db) of itsbandpass, thus assuring that light outside the desired excitation bandis prevented from reaching the optical read cells 620, and ultimatelythe optical detection assembly 906. Further, the laser filter 962 ispreferably mounted at an oblique angle off of its normal axis, e.g., 5°,so that the reflected light from the front and back surfaces of thelaser filter 962 cannot reenter the resonant laser cavity and modulatethe laser activity of the laser source 948.

[0401] C. Optical Detection Assembly

[0402] The purpose of the optical detection assembly 906 is to detectthe excited labeled antigen, and specifically fluorescent radiation fromthe CY5 dye, and produce a voltage signal that is directly proportionalto the concentration of dye in the optical read cell 620, and thusdirectly proportional to the concentration of target drug analyte in thesample. To this end, the optical detection assembly 906 comprises anoptical detector module 964 mounted within the detector aperture 922formed through the vertical flange 918 of the scanner head mechanism910. The optical detector module 964 includes a modular housing 966,which contains an optical detector 968 and an integral high-gainpreamplifier 970 (shown in FIG. 86). The optical detector 968 includes asilicon diode, and the high-gain preamplifier 970 is mounted on the samedye to minimize noise and thermal effects of the high impedance detectorcircuit. The high-gain integral preamplifier 970 has a 600 MΩ internalfeedback resistor (not shown), giving the circuit a relatively largeinternal gain. The optical detector 968 is mounted within the modularhousing 966, such that its sensing beam 976 intersects the optical readcells 620 at an angle transverse to the longitudinal axes of the opticalread cells 620. In the illustrated embodiment, this transverse angle is90° to maximize the amount of light sensed by the optical detector 968.

[0403] The optical detection assembly 906 further comprises an externalamplifier 972, which takes the preamplified signal (e.g., 10⁴ gain) fromthe preamplifier 970, and amplifies it by an additional factor, e.g.,10². The combined detector circuitry gain has a gain of one million (10⁶gain) in order to produce an output voltage of 1.4 volts for a CY5 dyeconcentration of 1.0×10⁻⁹ M. This is a combined gain within a factor of2 of what is obtainable with a highly sensitive photomultiplier tubedetector. Thus, the power supply for optical detection assembly 906preferably has a very low noise.

[0404] It should be noted that CY5 dye molecules absorb photons mostefficiently at 650 nm (λ_(ex max)=650 nm) and emit fluorescent photonsmost efficiently at 655 nm (λ_(em max)=655 nm). This gives a Stokesshift of only 5 nm, which is a relatively demanding optical requirement.As a result, the optical detection assembly 906 must be capable ofdetecting fluorescent photons with great sensitivity, whilesimultaneously rejecting incident light photons with high selectivity.To this end, the optical detection assembly 906 comprises a three-stagefilter 974, which includes two stages of 670 nm bandpass filters (±5 nmFWHM) to permit detection of fluorescent photons, and a single stage 655nm reject filter, which rejects light <655 nm and passes light >655 nmwith a steep slope between the two. Together these filters rejectincident photons of scattered light (<655 nm) while passing photons offluorescent light (>655 nm) with at least 50% efficiency for thethree-stage filter 974.

[0405] Together, the optical excitation assembly 904 and opticaldetection assembly 906 provide a Stokes shift of approximately 35 nm(670 nm-635 nm). While this is only about 50% as sensitive forfluorescent light detection as the optimal 5 nm Stokes shift, it doespermit acceptable rejection of scattered light (>10⁸:1 limit). This isequivalent to a background light of about 10⁻¹² M (i.e., 1 pM) CY5 dye.The combined optical excitation and optical detection assemblies 904 and906 has a linear dynamic range of about 10⁻¹¹ to 5×10⁻⁹ M CY5 dye orabout 2.5 decades of linear response to CY5 dye molecules. The flowimmunoassay assembly 600 has been optimized, so that the cutoff pointsfor each of the assay occur well within this range of CY5 dyeconcentration.

[0406] D. Optical Flow Immunoassay Scanning Assembly-Operation

[0407] Having now described the detail structure of the optical flowimmunoassay scanning assembly 900, its operation will now be described.During the afore-described buffer pre-wash, sample dispense, and bufferpost-wash cycles, the optical flow immunoassay scanning assembly 900senses any displaced labeled antigen flowing through the read cells 620and processes this information accordingly.

[0408] Specifically, the scanning drive assembly 926 is operated totranslate the scanner head mechanism 910, and thus, the laser beam ofthe laser source 948 and sensing beam of the optical detector 968simultaneously across the immunoassay flow channels. That is, the lasersource 948 transmits laser energy at an oblique entry angle, e.g., 45°,to the longitudinal axes of the read cells 620 lumens. The laser energyenters the optical transmission ports 790 of the read cell lumens 786,which is then transmitted down the longitudinal axes 958 of the readcells lumens 786. In response, any fluorescent labeled antigen flowingthrough the optical read cells 620 is excited into fluorescence, whichoptical energy is in turn transversely emitted from the fluorescedlabeled antigen through the walls of the read cells 620. At the sametime, the optical detector 968 senses the transversely emitted opticalenergy at an angle substantially perpendicular to the longitudinal axesof the read cell lumens 786.

[0409] Referring to FIG. 87, the optical detector 968 outputs a signalindicative of the sensed fluorescence level of the optical energy, whichis then received by the CPU 204 (FIG. 12). Because the optical detector968 scans through the immunoassay flow channels, a discrete outputsignal is generated for each of the immunoassay flow channels during asingle scan. As illustrated in FIG. 87, the CPU 204 takes these discreteoutput signals and constructs, for each immunoassay flow channel, afluorescence magnitude level waveform over time, i.e., over severalforward and reverse scans.

[0410] The position sensor 922 is gated to the CPU 204, such that theCPU 204 only processes the data for each immunoassay reaction chamberwhen a corresponding optical read cell 620 is detected, i.e., when thesensing beam of the optical detector 968 intersects the correspondingoptical read cell 620. That is, as the position sensor 922 senses aposition indicator 942, which in the illustrated embodiment is a notch,it outputs a high signal to the CPU 204, indicating that the sensingbeam 976 of the optical detector 968 is currently passing through thecorresponding optical read cell 620. As long as this signal is high, theCPU 204 processes the output signal received from the optical detector968. In contrast, when the position sensor 922 no longer senses aposition indicator 942, it outputs a low signal to the CPU 204,indicating that the sensing beam of the optical detector 968 iscurrently passing through a region between optical read cells 620. Aslong as the signal is low, the CPU 204 will not process the outputsignal received from the optical detector 968.

[0411] Turning now to the analysis of the detector signals, during thebuffer pre-wash, the buffer is flowed through the immunoassay reactionchambers 616 to wash out any displaced labeled antigen from theimmunoassay reaction chambers. The analyte detectable sample solution isthen flowed through the read cells 620. The buffer pre-wash continuesuntil all immunoassay flow channels have caused the requisite volume ofbuffer to flow through the immunoassay reaction chambers 616, so thateach has come to equilibrium, as demonstrated by each immunoassay flowchannel having achieved a constant background fluorescence level readoutof approximately 100 mV. As previously discussed, the illustratedembodiment flows 400 μl of buffer from the buffer chambers 614, whichhas been found to achieve equilibrium. This phenomenon is illustrated inFIG. 88, which shows a sharp increase in the fluorescence level detectedfrom the excited labeled antigen, and a drop off of the fluorescencelevel to a fluorescence reference level when the immunoassay reactionchamber 616 comes to equilibrium. The fluorescence reference level isused to establish normalization parameters for each of the respectiveimmunoassay flow channels by using the immunoassay flow channel havingthe greatest mean intensity as a reference value of 1.000 anddetermining the ratio of each immunoassay flow channel to this referenceimmunoassay flow channel. This provides a separate normalizationparameter for each immunoassay flow channel. For example, Table 1illustrates exemplary pre-wash reference values for five immunoassayflow channels and the respective calculated normalization factors foreach. As shown, immunoassay flow channel #3 exhibits the greatest meanfluorescence reference level, and is thus assigned a normalizationfactor of 1.00. The remaining immunoassay flow channels exhibit lesserfluorescent levels, and are thus assigned a normalization factor lessthan 1.00.

[0412] During sample flow after the buffer pre-wash, the sample isflowed through the immunoassay reaction chambers 616, which if itcontains the target drug analyte, displaces any remaining bound labeledantigen from the corresponding immunoassay reaction chamber 616. In anyevent, the analyte detectable sample solution then flows through theread cells 620. The sample flow continues until all of the sample hasflowed from the sample distribution chambers 612. If the sample doescontain the target drug analyte, the detected fluorescent level willincrease to a relatively high level, as illustrated in FIG. 88. If thesample does not contain the target drug analyte, the detectedfluorescent level will remain at the relatively low reference level.

[0413] After sample flow is completed, buffer post-wash is performeduntil all of the remaining sample has been pushed through theimmunoassay flow channels and into the waste chamber 622. As previouslydiscussed, the illustrated embodiment flows 250 μl more of buffer fromthe buffer chambers 614, which has been found to be suitable to push theremaining sample through the immunoassay flow channels. In the case,where the sample does contain the target drug analyte, the detectedfluorescence level will eventually decrease to the relatively lowreference level when the sample has indeed been flowed out of the readcells 620, as illustrated in FIG. 88. Of course if the sample does notcontain the target drug analyte, the detected fluorescence level willhave already been at the relatively low reference level, and will remainas such through the duration of the buffer post-wash.

[0414] After the buffer post-wash is completed, the amount of targetdrug analyte within the sample is quantified by first obtaining the meanfluorescent intensity of each of the immunoassay flow channels. The meanintensity of each of the immunoassay flow channels is then divided bytheir respective normalization factors, providing for a ratio-metricreadout that tends to cancel channel-to-channel optical differencesarising from slight optical differences caused by manufacturingtolerances in the injection molded plastic optical read cell assembly618. Table 1 illustrates exemplary sample mean values for the sample forthe five immunoassay flow channels, and the and the calculatedratiometric values for each. It is noted that although the means signalvalues for immunoassay flow channels #″s 1, 4, and 5 were less than thatof immunoassay flow channel #3, their ratiometric output signals aregreater than that of immunoassay flow channel #3 due to their relativelylow channel normalization factors. TABLE 1 Channel No. Ch. #1 Ch. #2 Ch.#3 Ch. #4 Ch. #5 Mean  95 mV  98 mV  100 mV  97 mV  99 mV Pre-washReference Value Channel 0.950 0.980 1.00 0.970 0.990 Normal- izationFactor Sample 1500 mV 1450 mV 1570 mV 1533 mV. 1610 mV Mean ValueRatiometric 1579 1480 1570 1580 1626 Value

[0415] It is noted that since immunoassay agglomerization reactionsrequire minutes/hours to reach completion, and the continuous flowimmunoassay reactions used in the system 100 occur within 3-5 minutes,the reactions are performed in kinetic/dynamic mode far from equilibriumconditions. Nevertheless, careful control of reaction parameters ensuresthat the concentration of the labeled antigen in the analyte detectablesample solution is representative of the original concentration of thetarget drug analyte contained in the original pure saliva sample. Aspreviously discussed, appropriate proportionality constants permittingcalibration of each of the immunoassay flow channels are contained inthe barcode information, which can be used in addition to the previouslydiscussed internally measured channel-to-channel normalization factors.

[0416] VIII. Alcohol Detection Assembly

[0417] Referring to FIGS. 6-8 and 89-96, the system 100 comprises analcohol detection assembly 1000, the purpose of which is to conduct aquantitative analysis of the concentration of ethanol in the buffersample solution and determine the mass-per-volume percentage (%_(w/v))of ethanol in the original sample of collected, undiluted saliva. In theillustrated embodiment, the alcohol detection assembly 1000 conducts anendpoint alcohol dehydrogenase (ADH) enzymatic assay on the sample inorder to quantitatively detect the alcohol in the sample. The alcoholdetection assembly 1000 generally comprises an alcohol reaction assembly1002 and an alcohol reader assembly 1004.

[0418] A. Alcohol Reaction Assembly-Cassette Portion

[0419] The purpose of the alcohol reaction assembly 1002 is to provide areaction between any alcohol in the sample and reagents, and thenpresenting this reaction for analysis. Referring specifically to FIGS.89-96, the portion of the alcohol detection assembly 1000 associatedwith the cassette 152 is illustrated. As can be seen, the alcoholdetection assembly 1000 is integrated with the previously described flowimmunoassay assembly 600, and specifically, the rotary valve 610, whichis operated to dispense the same sample to the alcohol detectionassembly 1000 as is distributed to the flow immunoassay assembly 600.The alcohol detection assembly 1000 generally includes a manifold 1002,an alcohol reaction chamber 1004, a reagent chamber 1006, a bufferchamber 1008 with an associated buffer dispense plunger 1010, acalibrator chamber 1012 with an associated calibrator dispense plunger1014, a sample chamber 1015 (which is the same as the through channel706(1) shown in FIG. 55), and a vent/air flow assembly 1016.

[0420] The manifold 1002 is configured to provide the necessaryinterface, e.g., fluid and air transfer, between the alcohol reactionchamber 1004 and the other components. Specifically, the manifold 1002comprises a main body 1018 that is composed of a suitable material, suchas polycarbonate. The manifold main body 1018 is mounted to the bottomof the stator 624 of the rotary valve 610 underneath the sample feedport 628, which as will be described in further detail below, allows forindirect receipt of the sample from the feed port 628. To the end, themanifold main body 1018 includes an arcuate surface 1020 thatcomplements the outer surface of the stator 624. The various channelsdisposed within the manifold 1002 will be described in further detailbelow.

[0421] Referring specifically to FIG. 93A, the reagent chamber 1006comprises a cylindrical column 1022 composed of a suitable chemicallyinsert material, such as injection molded polypropylene polymer. Thereagent chamber 1006 is configured to provide the components that reactin the presence of alcohol to produce an alcohol indicator. In theillustrated embodiment, the reagent chamber 1006 contains dry alcoholreagent, which is specifically produced by disposing 0.2 mM N-acetylcyseine, 1.8 μM nicotinamide adenine dinucleotide (NAD), 500 U/mlalcohol dehydrogenase (ADH), 0.01 M phosphate buffer (pH=7.5), 0.01%BSA, and 2% trehalose, and lyophilizing the components to stabilize themduring transportation and storage of the cassette 152. The reagentchamber 1006 is in fluid communication with the alcohol reaction chamber1004 through the manifold 1002. To this end, the manifold 1002 is seatedwithin a reaction chamber seat 1024 formed within the manifold 1002. Themanifold 1002 comprises a reagent channel 1026 that extendsperpendicularly between a stylus bore 1028, which extends from thereagent chamber seat 1028, and a reagent exit port 1030 leading to thealcohol reaction chamber 1004. To prevent permeation of water vapor, apair of puncturable seals 1032 and 1034 are bonded at the opposite endsof the reagent chamber 1006. The seals 1032 and 1034 are composed of asuitable material, such as an aluminum foil-lined/polymer bilayer seal.

[0422] The buffer chamber 1008 is longitudinally disposed along the sideof the rotary valve 610 underneath the buffer chamber seats 684, and isconfigured to rehydrate the lyophilized reagent within the reagentchamber 1006. The buffer chamber 1008 is cylindrical-shaped and iscomposed of a suitable material, e.g., injection molded polypropylene.The buffer chamber 1008 is in fluid communication with the reagentchamber 1006, and to this end, is suitably mated with the extreme end ofthe reagent chamber 1006. As with the other buffer chambers, the wallsof the buffer chamber 1008 are sufficiently thick and impermeable towater vapor during the storage lifetime of the cassette 152. The bufferchamber 1008 has a 1 ml capacity and contains a buffer solution suitablefor reconstituting the reagents within the reaction chamber 1005, e.g.,0.6 M TRIS/0.4 M lysine buffer (pH=9.7).

[0423] Referring specifically to FIG. 93A, the buffer chamber 1008comprises a cylindrical bearing surface 1038 with which the associatedbuffer dispense plunger 1010 sealingly mates. The buffer dispenseplunger 1010 comprises a rigid plunger head 1040, which includes anO-ring groove 1042 for seating of an O-ring (not shown). The O-ring ofthe buffer dispense plunger 1010 facilitates a sealing relationshipbetween the buffer dispense plunger 1010 and the bearing surface 1036 ofthe buffer chamber 1008. Originally, the buffer dispense plunger 1010 isdisposed within the buffer chamber 1008 at its extreme end, while apuncturable seal 1042 is bonded to the end of the buffer chamber 1008opposite the buffer dispense plunger 1010. The combination of the bufferdispense plunger 1010 and seal 1042 prevent water vapor from escapingthe confines of the buffer chamber 1008 during storage of the cassette152. The seal 1042 is composed of a suitable material, such as analuminum foil-lined/polymer bilayer seal.

[0424] The buffer dispense plunger 1010 further includes a stylus 1046,which is configured to puncture the seal 1044 at the other end of thebuffer chamber 1008. Movement of the buffer dispense plunger 1010towards the seal 1044, causes the stylus 1046 to puncture the seal 1044,allowing the buffer to flow from the buffer chamber 1008 through thereagent chamber 1006. During the buffer dispensing process, the stylus1046 extends through the reagent chamber 1006 and reagent chamber seat1028 (after puncturing the seals 1032 and 1034), coming to rest in thestylus bore 1028 at the end of the dispensing process. The flow ofbuffer through the reagent chamber 1006 rehydrates the lyophilizedreagent, producing a reconstituted reagent therein, which is in turn,dispensed into the alcohol reaction chamber 1004.

[0425] Referring specifically to FIG. 94D, the calibrator chamber 1012contains a calibrator solution having a known quantity of alcohol, whichin the illustrated embodiment, is 0.1 ml calibrator solution with aconcentration of 0.01% concentration of alcohol. The calibrator chamber1012 is cylindrical-shaped and is composed of a suitable material, e.g.,injection molded polypropylene. The calibrator chamber 1012 is in fluidcommunication with the alcohol reaction chamber 1004 via the manifold1002. To this end, the manifold 1002 includes a calibrator chamber seat1048 in which one end of the calibrator chamber 1012 is seated. Themanifold 1002 further includes an alcohol channel 1050 perpendicularlyextending between a stylus bore 1028, which extends from the seat 1048,and an alcohol exit port 1054 leading to the alcohol reaction chamber1004.

[0426] The calibrator chamber 1012 comprises a cylindrical bearingsurface 1056 with which the associated calibrator dispense plunger 1014sealingly mates. The calibrator dispense plunger 1014 comprises a rigidplunger head 1058, which includes an O-ring groove 1060 for seating ofan O-ring (not shown). The O-ring of the calibrator dispense plunger1014 facilitates a sealing relationship between the calibrator dispenseplunger 1014 and the bearing surface 1056 of the calibrator chamber1012. Originally, the calibrator dispense plunger 1014 is disposedwithin the calibrator chamber 1012 at its extreme end, while apuncturable seal 1062 is bonded within the calibrator chamber 1012opposite the calibrator dispense plunger 1014. The combination of thecalibrator dispense plunger 1014 and seal 1062 prevent the calibratorsolution from escaping the confines of the calibrator chamber 1012 andmanifold 1002 during storage of the cassette 152. The seal 1062 iscomposed of a suitable material, such as an aluminum foil-lined/polymerbilayer seal.

[0427] The calibrator dispense plunger 1014 further includes a stylus1064, which is configured to puncture the seal 1062 at the other end ofthe calibrator chamber 1012. Movement of the calibrator dispense plunger1014 towards the seal 1062, causes the stylus 1064 to puncture the seal1062 and extend through an aperture 1066 at the end of the calibratorchamber 1012, allowing the calibrator solution to flow through thealcohol channel 1050 into the alcohol reaction chamber 1004. At the endof the alcohol dispensing process, the stylus 1064 comes to rest in thestylus bore 1052.

[0428] The sample chamber 1015 is the same as the through channel 706(1)(shown in FIG. 59) that extends through the rotor 626 and forms part ofthe feed channel 712 in the flow immunoassay assembly 600. In theillustrated embodiment, the sample chamber 1015 contains 20 μl ofsample. When the rotary valve 610 is clocked in the sample flow/bufferpost-wash configuration, the sample chamber 1015 is rotated to avertical position, where it placed into fluid communication with thealcohol reaction chamber 1004, thereby acting as a shear valve.Specifically, the sample chamber 1015 communicates with a sampledispense port 1068 disposed through the bottom of the stator 624 (shownin FIG. 59). The manifold includes an access channel 1070 through whicha sample/vent tube 1071 extends. One end of the sample/vent tube 1071 isconnected to the sample dispense port 1068, while the other end of thesample/vent tube 1071 extends into the alcohol reaction chamber 1004.The sample remains in the sample chamber 1015 even when in the verticalposition, due to the surface tension of the sample. As will be describedin further detail below, the sample is forced out of the sample chamber1015 into the alcohol reaction chamber 1004 using air pressure, as willbe described below.

[0429] The alcohol reaction chamber 1004 is configured to collect thesample from the sample chamber 1015, the alcohol from the calibratorchamber 1012, and the reconstituted reagent solution from the reagentchamber 1006, and exhibit the analyte detectable sample solution to thealcohol reader assembly 1004 for calibration and detection of thealcohol within the sample. It is noted that the reagent solution, whichcontains NAD and ADH will react with the alcohol to produce an opticalenergy absorbing substance, and specifically, NAD with high energyhydrogen (NADH). As will be described in further detail below, theoptical energy absorbed by the NADH can be optically detected by thealcohol reader assembly 1004 to perform the calibration and detectionfunctions. To this end, the reaction chamber 1004 is composed of asuitably clear material, such as, acrylic polymer, and is rectangular inshape, which in the illustrated embodiment, has a pathlength of 0.500cm, a width of 0.8 cm, and a height of 2.5 cm. The top of the reactionchamber 1004 is open and is friction fit around the bottom of themanifold main body 1018.

[0430] The vent/air flow assembly 1016 is configured to perform threefunctions: (1) provide venting of air from the alcohol reaction chamber1004 during the dispensing processes; (2) providing air flow to thesample chamber 1015 to dispense the slug of sample into the alcoholreaction chamber 1004; and (3) sealing the sample within the samplechamber 1015 and alcohol reaction chamber 1004 after the cassette 152 isdiscarded. Specifically, the vent/air flow assembly 1016 comprises avent manifold 1072 composed of a suitable material, such aspolycarbonate. The vent manifold 1072 is mounted to the top of thestator 624 of the rotary valve 610 above the sample feed port 628. Tothe end, the vent manifold 1072 includes an arcuate surface 1074 thatcomplements the outer surface of the stator 624.

[0431] The vent/air flow assembly 1016 further comprises a channeledbarb fitting 1076 that is screwed into vent seat 1077 formed within thevent manifold 1072. The vent manifold 1072 includes a vent channel 1078,which extends from the vent seat 1077 down through the vent manifold1072, where it communicates with an air entry port 1080 disposed throughthe stator 624. When the rotary valve 610 is clocked in the sampleflow/buffer post-wash configuration (FIG. 95), thereby verticallypositioning the sample chamber 1015, the top of the sample chamber 1015is aligned with and communicates with the air entry port 1080 located atthe top of the stator 624, and the bottom of the sample chamber 1015, aspreviously described, is aligned with and communicates with the sampledispense port 1068 located at the bottom of the stator 624, which aswill be described in further detail below, facilitates conveyance of airflow through the sample chamber 1015 to dispense the sample into thealcohol reaction chamber 1004. In contrast, when the rotary valve 610 isclocked in the sample distribution/buffer pre-wash configuration (FIG.96), the air entry port 1080 and sample dispense port 1068 are exposedto the space 1082 within the stator 624, which as will be described infurther detail below, facilitating venting of air from the alcoholreaction chamber 1004.

[0432] The vent/air flow assembly 1016 further includes a flexibleconduit 1084, such as Tygon tubing, one of which is mated to the ventfitting 1076. The vent/air flow assembly 1016 further includes avent/air flow port 1086, which is suitably affixed to the other end ofthe flexible conduit 1084. The flexible conduit 1084 is of a suitablelength, e.g., 13 cm., to allow the vent/air flow port 1086 to be mountedwithin an vent/air flow port mounting aperture 188 on the side of thecassette case 154 (FIG. 3). Optionally, the vent/air flow port 1086 maybe self-sealing in that it includes a tightly disposed a hydrophobicseal (not shown), which allows air to pass therethrough, whilepreventing the biologically hazardous saliva from leaking out of thecassette 152 after its disposal following use.

[0433] Thus, when the rotary valve 610 is clocked in the sampleflow/buffer post-wash configuration (FIG. 95), the vent/air flow port1086 is placed into communication with the alcohol reaction chamber 1004via the flexible conduit 1084, vent fitting 1076, vent channel 1078, airentry port 1080, sample chamber 1015, sample dispense port 1068, andsample/vent tube 1071, thereby facilitating the dispensing of the samplefrom the sample chamber 1015 into the alcohol reaction chamber 1004 whenair is blown into the vent/air flow port 1086. When the rotary valve 610is clocked in the sample distribution/buffer pre-wash configuration(FIG. 96), the vent/air flow port 1086 is placed into communication withthe alcohol reaction chamber 1004 via the flexible conduit 1084, ventfitting 1076, vent channel 716, air entry port 1080, the interior of thestator 624, the sample dispense port 1068, and the sample/vent tube1071, thereby facilitating the venting of air out through the alcoholreaction chamber 1004 during the dispensing process.

[0434] B. Alcohol Reaction Assembly-Tester Portion

[0435] Having just described the portion of the alcohol reactionassembly 1002 associated with the cassette 152, the portion of thealcohol reaction assembly 1002 associated with the test console 102 willbe discussed. Referring to FIGS. 6-8, 13, and 14, the alcohol reactionassembly 1002 further includes a buffer driver 1102, calibrator driveassembly 1104, a vacuum port connector 1106, the previously describedcassette loading assembly 300 and vacuum pump 456, and a mixing driveassembly 1110.

[0436] The buffer driver 1002 (best shown in FIG. 14), which is affixedto the pin alignment flange 750 in a manner that aligns the bufferdriver 1002 with the buffer dispense plunger 1010 disposed within thebuffer chamber 1008. Thus, as the cassette loading assembly 300 isoperated to load the cassette 152 into the test console 102, the bufferdriver 1002 engages and displaces the buffer dispense plunger 1010within the buffer chamber 1008. A buffer driver access opening 190 isformed on the side of the cassette case 154 (shown in FIG. 3), therebyallowing the buffer driver 1002 to engage the buffer dispense plunger1010.

[0437] The calibrator drive assembly 1104 includes a linear stepperbuffer motor 1114, which is mounted to the motor mount 1116, and acalibrator driver 1118, which is aligned with the calibrator dispenseplunger 1014 within the calibrator chamber 1012 when the cassette 152 isloaded into the test console 102. Thus, when the calibrator driver 1118is driven towards the cassette 152, it engages and displaces thecalibrator dispense plunger 1014 within the calibrator chamber 1012. Acalibrator chamber access opening 192 is formed on the front 156 of thecassette case 154 (shown in FIGS. 3 and 4), thereby allowing thecalibrator driver 1118 to engage the calibrator dispense plunger 1014.

[0438] The vent/air flow port connector 1106 is mounted within anaperture 1112 disposed within the pin alignment flange 750 (best shownin FIGS. 13 and 14). In the illustrated embodiment, the vent/air flowport connector 1106 is similar to the previously described vacuum portconnector 450. Thus, the vent/air flow port connector 1106 is composedof a compliant silicone rubber in the form of bellows, a compliant rimof which forms a tight vacuum seal when engaged with the cassettevent/air flow port. In the illustrated embodiment, the vent/air flowport connector 1106 is 1.5 cm in length, and 1 cm in diameter, with itscompliant rim 2 mm in width.

[0439] The afore-described cassette loading assembly 300 is used as thevent/air flow port drive assembly. Thus, as the cassette 152 is loadedinto the test console 102, the vent/air flow port connector 1106 isengaged with the vent/air flow port 1086 located on the side of thecassette case 154, so that the compliant rim of the connector and thevent/air flow port 1086 coincide and provide a tight seal. Thepreviously described vent/air flow port mounting aperture 188 (shown inFIG. 3) allows vent/air flow port connector 1106 to engage the vent/airflow port 1086.

[0440] The other end of the vent/air flow port connector 1106 isconnected to vacuum tubing 1120, which is composed of a suitablematerial, such as Tygon tubing. The vacuum tubing 1120 is in turnconnected to one port of a vacuum outlet filter 1122, which is composedof a suitable material, such as 0.1 μm diameter port microporoushydrophilic PTFE. The other port of the outlet filter 1122 is connectedto a vacuum outlet port 1124 of the vacuum pump 456. Thus, the vacuumpump 456 can be operated to create positive pressure within the vent/airflow assembly 1016. It should be noted that the vent/air flow port driveassembly 1108 and vacuum pump 456 are both operated under control of aCPU 204 and I/O controller 206 (FIG. 12). A vent/air flow port drivehome sensor (generally shown in FIG. 12) is used to provide independentconfirmation that the vent/air flow port drive assembly 1108 has movedfrom or into its home position.

[0441] The mixing drive assembly 1110 includes a rotary mixing motor1126, which is mounted to the inside of the door 310, and a mixingcoupling (not shown) that is rotatably coupled to the mixing motor 1126,which is located adjacent the alcohol reaction chamber 1004 when thecassette 152 is loaded into the test console 102. The mixing couplingcontains two magnets (not shown), which when rotated by the mixing motor1126 magnetically interact with a ferrous element (not shown) within thealcohol reaction chamber 1004. In the illustrated embodiment, theferrous element is a 1.6 mm diameter stainless steel ball. It should benoted that the mixing drive motor assembly 1110 is operated undercontrol of a CPU 204 and I/O controller 206 (FIG. 12). A mixing motor1126 home sensor (generally shown in FIG. 12) is used to provideindependent confirmation that the coupling is in the home position,i.e., the magnet is located at it lowest point to ensure that theferrous element is disposed in the bottom portion of the alcoholreaction chamber 1102, so that dispensing operations are not interferedwith.

[0442] C. Alcohol Reader Assembly

[0443] The purpose of the alcohol reader assembly 1004 is to measure thereaction that takes place in the alcohol reaction chamber 1004 and toquantify any alcohol contained in the sample based on this measuredreactions. In the illustrated embodiment, the alcohol reader assembly1004 uses spectrophotometry to determine the absorbance level of thereacted solution, which absorbance level is proportional to the amountof alcohol in the reacted solution. To this end, the alcohol readerassembly 1004 generally comprises an optical transmission assembly 1150,an optical detection assembly 1152, and processing circuitry, which inthe illustrated embodiment, is the CPU 204.

[0444] The optical transmission assembly 1150 comprises an opticaltransmission module 1154 and a mount 1156 mounted to the main base sideflange 120. The mount 1156 has an aperture 1158 through which theoptical transmission module 1154 is mounted. The optical transmissionmodule 1154 includes a housing 1160 in which there is housed an opticalsource (not shown) that is aligned with and is configured to transmitoptical energy through the alcohol reaction chamber 1004, and thus theanalyte detectable sample solution, from the rear 158 of the cassettecase 154. An optical viewing window 194 is formed through the cassettecase 154 (shown in FIGS. 3 and 4) to expose the alcohol reaction chamber1004 on both sides of the cassette case 154, thereby allowing thetransmission of optical energy from the rear 158 of the cassette case154 where the optical transmission assembly 1150, out the front 156 ofthe cassette case 154.

[0445] The optical transmission assembly 1150 further includes a opticalbandpass filter (not shown) housed within the housing 1160, so that theoptical energy passing through the alcohol reaction chamber 1004 andanalyte detectable sample solution exhibits approximately monochromaticlight of suitable wavelength. In the illustrated embodiment, the opticalsource comprises a 0.75 mW UV light emitting diode (LED) with maximumlight emission at 375 nm, and the optical bandpass filter passes anoptical frequency of 365 nm (±5 nm FWHM). The optical transmissionassembly 1150 further comprises an optical 50:50 splitter 1160, whichsplits the energy beam from the optical bandpass filter into two energybeams, one of which is a reference energy beam that bypasses the alcoholreaction chamber 1004, and the other of which is the energy beam thatpasses through the alcohol reaction chamber 1004. As will be described,in further detail below, the reference energy beam is used to ensurethat the optical source transmits a uniform quantity of optical energythrough the alcohol reaction chamber 1004.

[0446] The optical detection assembly 1152 comprises a first opticaldetection module 1164 located at the front 156 of the cassette case 154adjacent the optical viewing window 194. The optical detection module1164 is mounted within an aperture 1166 formed within the mechanicalbench 908, such that it receives the optical energy beam transmittedthrough the alcohol reaction chamber 1004. The optical detectionassembly 1152 further comprises a second optical detection module 1168mounted within a beam splitter 1170 in which the optical transmissionmodule 1164 is associated. Thus, the second optical detection module1168 receives half of the optical energy from the optical transmissionmodule 1154 in the form of a reference optical energy beam.

[0447] In the illustrated embodiment, each of the optical detectionmodules 1164 and 1168 comprises a blue-sensitive silicon diode. Thefirst optical detection module 1164 receives the energy beam from thealcohol reaction chamber 1004 and outputs a signal indicative of theamount of optical energy received by it. As will be described in furtherdetail, this output signal is processed by the CPU 204 to calibrate thealcohol detection assembly 1000 and quantify the amount of alcohol inthe sample. The second optical detection module 1168 receives thereference energy beam directly from the optical transmission module 1154and also outputs a signal indicative of the amount of optical energyreceived by it. This output signal is used as feed back to avoltage-controlled current source controller module (not shown), whichensures that the optical transmission module 1154 is outputting auniform optical energy intensity.

[0448] D. Alcohol Detection Assembly-Operation

[0449] Having now described the detail structure of the alcoholdetection assembly 1000, its operation will now be described. Ingeneral, the alcohol detection assembly 1000 reacts the sample with thereagent solution to produce an alcohol detectable sample solution havingan alcohol indicator. In the illustrated embodiment, any alcohol withinthe sample is reacted in the presence of NAD, using ADH to effect theoxidation of the alcohol to acetaldehyde with a simultaneous reductionof NAD to NADH. When reacted to completion, a number of moles of NADHequal to the number of moles of alcohol is produced. Thus, theconcentration of NADH is proportional to the concentration of alcoholwithin the sample.

[0450] The concentration of the NADH in the alcohol detectable samplesolution can be measured by determining the change in absorbance betweenthe blank reagent solution, which does not contain alcohol, and thealcohol detectable sample solution, which does contain alcohol if thesample does. That is, according to the Beer-Lambert Law (commonly knownas Beer's law), the common logarithm of the intensity of signal (i.e.,voltage output) from an optical detector is inversely proportional tothe concentration of NADH in the alcohol detectable sample solution. Toeliminate any unknown parameters from the sample quantificationcalculation, the system is first calibrated by reacting the calibratorsolution with the reagent solution to produce an alcohol detectablecalibrator solution.

[0451] Thus, the concentration of alcohol in the sample can becalculated using the following equations:

F=C/(A ₁ −A ₀);

P=F*(A ₂ −A ₀)*1.02,

[0452] where F is the calibration factor; C is the concentration ofalcohol in the alcohol detector calibrator solution, which is 0.001 inthe illustrated embodiment; A0 is the measured absorbance of the blankreagent solution, A1 is the measured absorbance of the alcoholdetectable calibrator solution, A2 is the measured absorbance of thealcohol detectable calibrator solution; and P is the weight-per-volumeconcentration of alcohol in the alcohol detector sample solution. It isnoted that the factor 1.02 corrects for the dilution of the alcoholdetectable sample solution by the sample. The weight-per-volumeconcentration of alcohol in original sample can then be obtained fromthe weight-per-volume concentration of alcohol in the alcohol detectorsample solution (P), keeping in mind that the buffered sample solutiondispensed in the alcohol reaction chamber 1004 has been diluted 1:1 by abuffer.

[0453] Thus, as will now be described in further detail, the alcoholdetection assembly 1000 is operated to (1) produce and measure theabsorbance of the blank reagent solution; (2) produce and measure theabsorbance of the alcohol detectable calibrator solution; and (3)produce and measure the absorbance of the alcohol detectable samplesolution.

[0454] The blank reagent solution is produced by operating the cassetteloading assembly 300 to move the cassette carriage 302, and thus thecassette 152, towards the buffer driver 1002 affixed within the testconsole 102. As the buffer driver 1002 engages and displaces the bufferdispense plunger 1010 within the buffer chamber 1008, the stylus 1046punctures the seal 1044 in the buffer chamber 1008, and the seals 1032and 1034 in the reagent chamber 1006. This allows the buffer to flowthrough the alcohol reaction chamber 1004, thereby hydrating the dryreagent, and exiting the reagent chamber 1006 as reconstituted reagentsolution. The blank reagent solution then flows through the reagentchannel 1026 within the manifold 1002 and into the reagent chamber 1006via the reagent exit port 1030. The mixing drive assembly 1110 is thenoperated for a period of time, e.g., 1 minute, to move the ferrouselement within the alcohol reaction chamber 1004, thereby quantitativelymixing the blank reagent solution.

[0455] The absorbance of the blank reagent solution is measured byoperating the alcohol detection assembly 1000. Specifically, opticalenergy is transmitted from the optical transmission module 1154 throughthe blank reagent solution, where it is received by the first opticaldetection module 1164. The first optical detection module 1164 thenoutputs a signal, which is received and used by the CPU 204 to determinethe absorbance of the blank reagent solution. It is noted that thesecond optical detection module 1168 continuously receives the referenceoptical energy to provide feedback and effect uniform transmission ofoptical energy from the optical source.

[0456] The alcohol detectable calibrator solution is produced byoperating the calibrator drive assembly 1104 to move the calibratordriver 1118 into engagement with the calibrator dispense plunger 1014,which is displaced within the calibrator chamber 1012. Duringdisplacement of the calibrator dispense plunger 1014, the stylus 1064punctures the seal 1062 within the calibration chamber 1012, allowingthe calibrator solution to flow from the calibrator chamber 1012,through the alcohol channel 1050 within the manifold 1002, and into thealcohol reaction chamber 1004 via the alcohol exit port 1054. The mixingdrive assembly 1110 is again operated for a period of time, e.g., 1minute, to move the ferrous element within the alcohol reaction chamber1004, thereby mixing the unreacted calibrator solution and the blankreagent solution to form a fully reacted alcohol detectable calibratorsolution.

[0457] The absorbance of the alcohol detectable calibrator solution ismeasured by operating the alcohol detection assembly 1000 again.Specifically, optical energy is transmitted from the optical module 1154through the alcohol detectable calibrator solution, where it is receivedby the first optical detection module 1164. The first optical detectionmodule 1164 then outputs a signal, which is received and used by the CPU204 to determine the absorbance of the alcohol detectable calibratorsolution.

[0458] The alcohol detectable sample solution is produced by operatingthe rotary valve drive assembly 730 to clock the rotary valve 610 intothe sample flow/buffer post-wash configuration, thereby placing thesample chamber 1015 into the vertical position. The vent/air flowconnector drive assembly is operated to engage the vent/air flow portconnector with the vent/air flow port 1086. It is noted that this can beperformed during the previous steps. The vacuum pump 456 is thenoperated to provide a short burst of compressed air, e.g., 1 second, toforce air through the vent/air flow assembly 1016, and thus, the sampleout of the sample chamber 1015, through the sample/vent tube 1071 andinto the alcohol reaction chamber 1004. The mixing drive assembly 1110is then operated to move the ferrous element within the alcohol reactionchamber 1004, thereby mixing the unreacted sample and the alcoholdetectable calibrator solution to form a fully reacted alcoholdetectable sample solution. It is noted that if the sample containsalcohol, additional NADH is produced.

[0459] The absorbance of the alcohol detectable sample solution ismeasured by again operating the alcohol detection assembly 1000.Specifically, optical energy is transmitted from the optical module 1154through the alcohol detectable calibrator solution, where it is receivedby the first optical detection module 1164. The first optical detectionmodule 1164 then outputs a signal, which is received and used by the CPU204 to determine the absorbance of the alcohol detectable samplesolution.

[0460] With knowledge of the measured absorbances of the blank reagentsolution (A₁), alcohol detectable calibrator solution (A₂), and alcoholdetectable sample solution (A₃), as well as the known mass of alcohol inthe calibrator solution (M), the CPU 204 calculates theweight-per-volume percentage of alcohol in the alcohol detectable samplesolution (P), and thus, the original sample.

[0461] IX. Temperature Control Assembly

[0462] Referring to FIGS. 7, 8, and 97, the system 100 comprises atemperature control assembly 1200, the purpose of which is to bring theinternal assemblies of the cassette 152 to a desired controlled constanttemperature, thus providing consistency and predictability to thechemical reactions that occur within the cassette 152. The temperaturecontrol assembly 1200 is an independent hardware-only assembly thatfunctions independently of the CPU 204. This permits temperature controlto function continuously while the CPU 204 performs other housekeepingfunctions, such as sensor QC control tests.

[0463] The temperature control assembly 1200 includes a heater assembly1202 and a heater controller (not shown) that periodically turns theheater assembly 1202 on and off to maintain the temperature of thesystem 100 as measured by temperature sensors (not shown) disposed atstrategic locations within the test console 102. The heater assembly1202 includes internal heating elements 1208, a heat shroud adapter1210, and a heat vent adapter 1212. The temperature control assembly1200 further includes a cooler (not shown), which remains on to providea constant level of cooling of the cassette 152 sufficient to lower theambient temperature of the cassette 152 from its maximum initial ambienttemperature (10-40° C. in the illustrated embodiment) to the desiredcassette control temperature (37° C. in the illustrated embodiment).

[0464] The temperature control assembly 1200 further include a fan 1216,which is mounted to a fan bracket 1228, a flexible heat vent 1218, and aheat shroud 1220 to provide recirculation of the controlled temperatureair. One end of the heat vent 1218 is connected to the fan 1216, whilethe other end of the heat vent 1218 is connected to the heat ventadapter 1212 of the heater assembly 1202. The heat shroud adapter 1210of the heater assembly 1202 is in turn connected to the heat shroud1220. The heat shroud 1220 tapers to a rectangular tapered end 1222,which mates with a complementary rectangular opening 1224 (FIG. 85)formed in the mechanical bench 908 of the dynamic scanning assembly 902.A complementary rectangular opening 1226 (FIG. 14) is also formed in thefront support flange 304 of the cassette carriage 302. Thus, therectangular tapered end 1222 of the heat shroud 1220 aligns with variousopenings formed in the cassette case 154 for providing thermal access tothe internal components with the cassette 152.

[0465] Referring to FIGS. 3-5, a first series of heat vents 196 isformed on the front 156 of the cassette case 154 adjacent the bufferchambers 614. A second series of heat vents 198 is formed on the front156 of the cassette case 154 adjacent the sample distribution chambers612. A third series of heat vents 199 is formed on the rear 158 of thecassette case adjacent the angled rigid tubes 650 of the buffer chambers614. Thus, thermally controlled air exiting the rectangular tapered end1222 of the heat shroud 1220 enters the cassette case 154 through thefirst and second series of heat vents 196 and 198, thereby exposing theinternal components of the chemistry cassette 152 to the air, which thenexits the cassette case 154 out through the third series of heat vents199 on the rear 158 of the cassette case 154.

[0466] In the illustrated embodiment, the heater assembly 1202 comprisesa 350W resistive heater, and the heater controller is aproportional/differential/integral solid-state heater controller. Thetemperature sensors are thermistors that are placed in mechanicalcontact with the cassette case 154, thereby providing intimate thermalconductivity with the cassette case 154, or alternatively, IR-sensitivethermocouples or thermopiles (shown as thermopile 1214 in FIG. 9) thatare optically coupled to the buffer chambers 614 near the middle of thecassette 152. Thus, if the cassette 152 is determined to be below thedesired temperature, the heater controller places the temperaturecontrol assembly 1200 in heat mode by turning on the heater assembly1202. As a result, heat proportional to the difference between thedesired cassette temperature and the ambient measured temperature of thecassette case 154 is produced.

[0467] The heater controller controls the amount of heat added to theconstantly recirculating air through the closed loop temperature controlassembly 1200 by incorporating sufficient anticipation to ramp down theheat added to the temperature control assembly 1200, so that thetemperature of the cassette 152 does not stray outside (i.e., overshootor undershoot) a transitional temperature range (e.g., ±2° C.) on theinitial thermal cycle, and does not stray outside a lesser steady-statetemperature range (e.g., ±1° C.) during subsequent thermal cycles. Oncethe temperature of the cassette 152 is determined to be in this smallerrange, only sufficient heat is added to keep the cassette 152 within thecontrol range, which provides a counteracting effect to the constantlyoperating cooler 1208.

[0468] X. Cassette Case

[0469] Turning now to FIGS. 98-101, the internal structural details ofthe cassette case 154 will now be described. The cassette case 154 canbe generally divided into front and rear panels 1302 and 1304 that fittogether in a clam-shell fashion. For the purposes of this discussion,the relative terms “upward” and “downward” will respectively meantowards the top and bottom sides of the cassette case; “leftward” and“rightward” will respectively mean towards the left and right sides ofthe cassette case looking towards the back of the cassette case 154; and“forward” and “rearward” means towards the front and back of thecassette case 154.

[0470] The cassette case 154 comprises an internal mixing assemblycompartment 1306, which is formed when the front and rear panels 1302and 1304 are mated together. The mixing assembly compartment 1306 can bedivided into a separate buffer chamber compartment 1308, samplecollection chamber compartment 1310, mixing chamber compartment 1312,and sample dispense plunger compartment 1314, which respectively containand support the buffer chamber 502, sample collection chamber 412,mixing chamber 504, and plunger body 520 of the mixing assembly 500. Itwill appreciated that structure disclosed as providing mechanicalsupport to a particular component of the mixing assembly 500 willprovide similar mechanical support to the entire mixing assembly 500 tosome extent, since the mixing assembly 500 can, in general, beconsidered a rigid body.

[0471] The mixing chamber compartment 1312 comprises first and secondsupport flanges 1316 and 1318, which extend from the rear panel 1304 atthe top and bottom of the mixing chamber compartment 1312. The bottomsurface of the first flange 1316 abuts the top of the mixing chamber504, and the top surface of the second flange 1318 abuts the bottom ofthe mixing chamber 504, thereby supporting the mixing chamber 504 in thepresence of force applied to it in the upward and downward directions.Of significance is the prevention of the upward and downward movement ofthe mixing chamber 504 when the sample and buffer drive assemblies 732and 734 are operably associated with mixing assembly 500. The sampledispense plunger compartment 1314 further comprises an actuate opening1320 provided within the second flange 1318 through which the sampledispense plunger body 520 is disposed.

[0472] The buffer chamber compartment 1308 comprises the afore-describedfirst support flange 1316 and a third support flange 1322, which isformed by complementary support flange sections 1324 and 1326 extendingfrom the tops of the front and rear panels 1302 and 1304. An arcuateseat 1328 is formed within the flange section 1326, and an opposingarcuate seat 1330 is formed within a fourth flange 1332 extending fromthe front panel 1302. Thus, when the front and rear panels 1302 and 1304are mated together, the arcuate section 1330 receives the bottom of thebuffer chamber 502, and the arcuate section 1328 receives the top of thebuffer chamber 502, thereby supporting the buffer chamber 502 in thepresence of force applied to it in the leftward, rightward, forward, andrearward directions.

[0473] The sample collection chamber compartment 1310 comprises theafore-described third support flange 1322, and a fifth support flange1334 extending from the rear panel 1304 at the bottom of the samplecollection chamber compartment 1310. The chamber stand 482 of the samplecollection chamber 412 rests on the fifth support flange 1334, therebysupporting the sample collection chamber 412 in the presence of forceapplied to it in the downward direction. Of significance is theprevention of any downward movement of the sample collection chamber 412when the vacuum port connector 450 is operably associated with themixing assembly 500. As a result, any shear or bending stress otherwisecreated between the sample dispense port 530 and the sample inlet port506 of the mixing chamber 504 is minimized.

[0474] The cassette case 154 further comprises an internal flowimmunoassay assembly compartment 1336, which is formed when the frontand rear panels 1302 and 1304 are mated together. The flow immunoassayassembly compartment 1336 can be divided into a separate buffer chamber,rigid tube, distribution chamber, upper chamber, and rotary valvecompartments 1338, 1340, 1342, 1344, and 1346, which respectivelycontain the buffer chambers 614, the rigid tubes 650, the sampledistribution chambers 612, the immunoassay reaction chambers 616, readcell assembly 618 and waste chamber 622, and the rotary valve 610. Itwill appreciated that structure disclosed as providing mechanicalsupport to a particular component of the flow immunoassay assembly 600will provide similar mechanical support to the entire flow immunoassayassembly 600 to some extent, since the flow immunoassay assembly 600can, in general, be considered a rigid body.

[0475] The buffer chamber compartment 1338 comprises sixth and seventhsupport flanges 1348 and 1350, which extend from the rear panel 1304 atthe top and bottom of the buffer chamber compartment 1338. The bottomsurface of the sixth support flange 1348 abuts the top of the bufferchambers 614, and the top surface of the seventh support flange 1350abuts the bottom of the buffer chambers 614, thereby supporting thebuffer chambers 614 in the presence of force applied to them in theupward and downward directions. Significantly, upward movement of thebuffer chambers 614 are prevented when the buffer drive assemblies 734are in operable association with the flow immunoassay assembly 600. Aneighth flange 1352 extends from the front panel 1302 at the bottom ofthe buffer chamber compartment 1338. The buffer chamber compartment 1338comprises a series of ten buffer chamber seats 1354, which are formedfrom a series of ten arcuate openings 1356 formed on top of the seventhflange 1350 and a complementary series of ten arcuate ledges 1358 formedon the eighth flange 1352 at the bottom of the front panel 1302. Whenthe front and rear panels 1302 and 1304 are mated together, thecomplementary arcuate openings 1356 and ledges 1358 abut each other toform the completed buffer chamber seats 1352. Thus, the bottoms of thebuffer chambers 614 can be seated within the corresponding seats 1352,thereby supporting the buffer chambers 614 in the presence of forceapplied to them in the leftward, rightward, forward, and rearwarddirections.

[0476] The rigid tube compartment 1340 comprises the afore-describedsixth support flange 1348 and a ninth support flange 1356, which extendfrom the rear panel 1304 at the top and bottom of the rigid tubecompartment 1340. The bottom surface of the ninth support flange 1356abuts the angled portion of the rigid tubes 650, thereby supporting therigid tubes 650 in the presence of force applied to them in the upwarddirection. Of significance, upward movement of the rigid tubes 650 isprevented when the buffer drive assemblies 734 are in operableassociation with the flow immunoassay assembly 600. The rigid tubecompartment 1340 also comprises a first and second series of ten arcuateseats 1358 and 1360 respectively formed in the sixth and ninth supportflanges 1348 and 1356 at the bottom and top of the rigid tubecompartment 1340. The first and second series of arcuate seats 1358 and1360 receive the rigid tubes 650 at their top and bottom, therebysupporting the rigid tubes 650, and thus further supporting the flowimmunoassay assembly 600 in the left, right, and back lateraldirections.

[0477] The sample distribution chamber compartment 1342 comprises thepreviously described ledge 180, which is formed by the front panel 1302.The top surface of the ledge 180 abuts the bottom of the sampledistribution chambers 612, thereby supporting the sample distributionchambers 612 in the presence of force applied to them in the downwarddirection. The sample distribution chamber compartment 1342 alsocomprises a tenth flange 1362 extending from the front panel 1302 in themiddle of the sample distribution chamber compartment. A series of tenarcuate seats 1364 are formed in the tenth flange 1362, and receive thesample distribution chambers 612, thereby supporting the sampledistribution chambers 612 in the presence of force applied to them inthe leftward and rightward directions.

[0478] The upper chamber compartment 1344 comprises a front wall 1366 aneleventh flange 1368 formed by the upper portion of the front panel1302, and a ridge 1370 formed on the upper portion of the rear panel1304. The front surface of the read cell assembly 618 abuts the surfaceof the front wall 1366, and the top back surface of the read cellassembly 618 abuts the ledge 180. Thus, the read cell assembly 618 issupported against any force applied to it in the forward and rearwarddirections. The bottom surface of the eleventh flange 1368 abuts the topof the read cell assembly 618, thereby supporting the read cell assembly618 against any force applied to it in the upward direction.Significantly, the upward movement of the read cell assembly 618 isprevented when the sample drive assemblies 732 are operably associatedwith the flow immunoassay assembly 600.

[0479] The rotary valve compartment 1346 comprises an annular relief1370 formed within the inner surface of the front panel 1302. Theannular relief 1370 receives one side of the cylindrical wall 668 of thestator 624, thereby supporting the rotary valve 610 in the presence offorce applied to it in the forward direction. The rotary valvecompartment 1346 also a series of ten arcuate seats 1374 that are formedin the eleventh flange 1368, and receive the immunoassay reactionchamber seats 688 of the stator 624, thereby supporting the rotary valve610 in the presence of force applied to it in the leftward and rightwarddirections.

[0480] The cassette case 154 further comprises various openings forproviding thermal access to the various components of the flowimmunoassay assembly 600, including the previously mentioned first,second, and third series of heat vents 196, 198, and 199, which areformed on the front and rear panel 1302 and 1304. The cassette case 154also comprises the previously described pair of homing pin holes 164 onthe front panel 1302. The cassette case 154 further comprises variousopenings for providing access to the internal components of thechemistry cassette 152, including the previously mentioned verticalaccess slot 174, horizontal access slot 172, routing slot 175, sampledistribution chamber access openings 178, sensor access opening 168,optical read slits 184, optical excitation apertures 186, vent/air flowport mounting aperture 188, calibrator chamber access opening 192, andoptical viewing window 194. These openings can be easily understood froma review of the intact cassette case 154, and will not be discussedfurther.

[0481] The cassette case 154 further includes the previously mentionedbuffer chamber access opening 170, vacuum port access opening 166,buffer chamber access openings 182, rotary valve access opening 176, andbuffer driver access opening 190 which will now be described in furtherdetail. The buffer chamber access opening 170 and vacuum port accessopening 166 are formed by cooperation between the front and rear panels1302 and 1304. Specifically, the buffer chamber access opening 176 isformed from the previously described arcuate opening 1328 formed in theflange section 1326 of the rear panel 1304, and a complementary arcuateopening 1372 formed on the flange section 1324 of the front panel 1302when the front and rear panels 1302 and 1304 are mated together. Thevacuum port access opening 166 is also formed from complementary arcuateopenings 1374 and 1376 formed within the flange sections 1324 and 1326when the front and rear panels 1302 and 1304 are mated together.

[0482] The buffer chamber access openings 182 are formed from arcuateopenings 1378 formed in the eighth flange 1352 at the bottom of thebuffer chamber compartment 1308, and complementary arcuate openings 1380formed in a thirteen flange 1382 directly below the seventh flange 1350when the front and rear panels 1302 and 1304 are mated together. Therotary valve access opening 176 is formed from complementary arcuateopenings 1384 and 1386 within the side walls of the front and rearpanels 1302 and 1304 when mated together. The buffer driver accessopening 190 is formed from complementary arcuate openings 1388 and 1390within the side walls of the front and rear panels 1302 and 1304 whenmated together. In addition, a series of five guiding holes (not shown)extend through the cassette case 154 in longitudinal alignment withbuffer drive access opening 190, thus receiving the buffer driver 1002when inserted into the buffer driver access opening 190. The guidingholes are formed from complementary arcuate openings (not shown) formedfrom opposing flanges (not shown) extending respectively from the insidesurfaces of the front and rear panels 1302 and 1304.

[0483] XI. User Interface Assembly

[0484] Referring to FIG. 1, the system 100 includes a user interface 150for providing information to, and receiving information from, anadministrator/operator. The user interface 150 includes an LCD displayscreen 152, which displays menu items, information request prompts, andtest results to the operator, and an internal printer 154, whichprovides the test results on hardcopy upon request by the operator. Theuser interface 150 further includes a keyboard (not shown) and keys 156for entering requested information into the system 100. The keys 156include (1) a set of alpha-numeric keys 158 for entering numericalinformation into the user interface 150; (2) a set of arrow keys 160 forscrolling between menu items; and (3) a set of four soft function keys162, which, depending on the menu item displayed, may be assigned“cont,” “accept,” “menu,” “return,” “cancel,” “previous,” “next,”“back,” “yes,” “no,” “print,” or “done” functions, which appear at thebottom of the display screen 152 for viewing by theadministrator/operator.

[0485] Specifically, depression of the following soft function keys 162will provide the following functions: (1) “cont” will accept a selectedmenu item (highlighted by manipulation of the arrow keys 160) and takethe user to the next screen or menu; (2) “accept” will accept theproperly entered information and take the user to the next screen ormenu; (3) “menu” will take the user back to the main menu if in the testmode or the administration menu if in the administration mode; (4)“return” will return the user to the next higher level menu; (5)“cancel” will place the system in cancel mode; (6) “previous” will takethe user to a previous same level menu or screen; (7) “next” will takethe user to the next same level menu or screen; (8) “back” will returnthe user to a previously selected same level menu or screen; (9) “yes”will give an affirmative answer to a posed question and take the user tothe next menu or screen; (10) “no” will give a negative answer to aposed question and take the user to the next menu or screen; (11)“print” will print test results; and (12) “done” will be return the userto the main menu. The CPU 204 is programmed to implement the menu-drivenuser interface 150.

[0486] XII. System and User Level Operation

[0487] Having described the detailed structure and operation of theassemblies of the system 100, the overall operation of the system 100will now be described. Referring to FIG. 102, the system 100 runsthrough a battery of tests and monitoring processes. The system 100 isfirst initialized at action block 1400, e.g., immediately upon power-up(cold-start), or after any interruption of normal operations or systemreset (warm-start). During system initialization, the CPU 204 performsan initialization process in which all software variable parameters areinitialized, including counters and pointers to data tables, with valuesnecessary for correction operation of the software. The core BIOSprovides the initialization of all hardware resources and provides aflag to the power on self-test that the initialization process hasoccurred satisfactorily.

[0488] At action block 1402, the CPU 204 performs a power on self-testduring which the various assemblies are tested to determine that thetest console 102 is capable of performing the desired functions for itscorrect operation. Any failure of a assembly component causes a QCmessage to indicate the type of failure and not allow the operator torun a test. Immediately following successful completion of the power onself-test, the CPU 204, at action block 1404, performs an initialsensor/interlock test during which all of the sensors will be read bythe CPU 204 for proper initial state/operation.

[0489] Following the completion of the foregoing tests, the system 100is placed into a Ready mode at action block 1408 during which allassemblies are fully powered and chemical testing can be initiatedimmediately upon insertion of a cassette 152 into the cassette port 106on the front of the test console 102. If no cassette insertion or keypador keyboard operation is sensed within a predetermined period of time(decision block 1406), e.g., 5 minutes, the CPU 204 will place thesystem 100 into Standby mode (action block 1408) during which only thecassette port 106 and the keypad/keyboard ports are power on. Insertionof the chemistry cassette 152 or pressing any key on the keypad orkeyboard will cause the CPU 204 to place the system 100 back into Readymode (action block 1404).

[0490] When the system 100 is placed into Ready or Standby mode, the CPU204 continuously monitors power supply voltages and sensor/interlockfunctions for satisfactory operation. A fault in any of the power supplyvoltages and sensor/interlock functions generates a fault condition,which generates an error flag on the display screen 152 and halts anyfurther analytical operation of the test console 102 until the faultcondition has been cleared. Any error flags indicative of faults in thesystem 100 are permanently logged into the nonvolatile memory of thereader device. Further, during idle operation time, the test console 102will periodically perform a diagnostic self test to determine properfunction of the various assemblies and certify the system's ability toconduct the testing functions. In the event that a new cassette 152 isinserted into the test console 102, any diagnostic self-test currentlyunderway will be cancelled, and the test console 102 will thenimmediately return to its normal Ready (analytical) mode of operation.

[0491] Referring now to FIG. 103, once the system 100 has been poweredon and has run through various initialization tests, theadministrator/operator is given the option to place the system 100 in anadministrative mode, an operation mode, and a recall mode (action block1410). In the administration mode, an authorized administrator maydefine the operational parameters of the system 100, e.g., recordspecific operator and facility information, customize test panels,change the test parameters, setup display and printer options, etc. Inthe operation mode, an authorized operator may input test subjectinformation and conduct tests using the system 100, but may not alterpredefined parameters that change the function of the system 100 (whichcan only be accomplished by the administrator). In the recall mode, anauthorized operator may recall previously performed and stored testsalong with corresponding subject information.

[0492] If at action block 1410, the user selects the “AdministrativeMode,” the system 100 first prompts the operator/administrator for hisor her user name and password (action block 1412). Thus, only authorizedadministrators can modify the operational parameters of the system 100.Upon entry of his or her correct user name and password, the system 100is prompted to select a specific language (e.g., English, Spanish,French, and German) that the operator will use to communicate with thesystem 100 (action block 1414). In alternative embodiments, the specificlanguage will not be selectable, but rather will default to the languageof the country in which the system 100 is ultimately shipped. Uponselection of the language, the system 100 prompts the administrator toselect the type of administration information (e.g., facilityinformation, general setup information, date/time information,authorized operator, test panel, units/threshold, and output optioninformation) to be programmed into the system 100 (action block 1416).

[0493] Specifically, selection of the “Facility” choice prompts theadministrator to enter facility specific information, such as the nameand location of the facility where the test is being run, as well as anycomments. Selection of the “General Setup” choice prompts theadministrator to input general setup information, such as whether anoperator password and/or subject identification information is required.For example, if test results are to be used as evidentiary purposes,e.g., at a police station or workplace, the administrator would likelyrequire an operator password and subject information to be entered. If,on the other hand, the test results are to be used merely to determinethe state of the test subject, e.g., in an emergency hospital room, theadministrator would likely not require an operator password and subjectinformation to be entered. The administrator may also select whether anoperator must enter the operator password/subject identification at thebeginning of every test. Selection of the “Date/Time” choice prompts theadministrator to enter date/time information, such as the current date,time, and daylight savings information.

[0494] Selection of the “Authorized Operator” choice prompts theadministrator to further select the operators authorized to operate thesystem 100. Specifically, the administrator may add an operator to alist of those authorized to operate the system 100 by entering anoperator user ID and associated password that is to be assigned to theadded operator. The administrator may select whether the added operatoralso has administrative privileges, i.e., whether the operator canmodify the administrative parameters of the system 100. Theadministrator may also remove an operator from the authorization list.

[0495] Selection of the “Test Panel” choice prompts the administrator tofurther select the specific tests that are to be run within each of amultitude of specific test panels. Thus, the system 100 allows theadministrator to customize test panels that are to be run on the system100. These test panels can be preprogrammed into the system 100, butultimately can be modified by the administrator. For example, theadministrator may customize the test panels to a workplace environment.Here, the workplace test panels may include, e.g., pre-employment,post-accident, random, or reasonable cause (the name of which has beenpreprogrammed or typed in by the administrator), as well as customtests. It should be noted, however, that the system 100 can becustomized to other scenarios besides the workplace, e.g., at a policestation or hospital emergency room. Selection of one of the test panels,whether it be specifically named or one the custom test panels, allowsthe administrator to select the specific drugs that are to be tested forthe selected test panel.

[0496] Selection of the “Units/Threshold” prompts the administrator toinput unit and threshold information for each of the list of specifictests that can be run on the system 100. Selection of the “OutputOption” prompts the administrator to further select how the test resultswill be exhibited and stored. For example, the administrator may selectthe type of data that will be displayed as the test results, e.g.,quantitative, threshold level, interpretative, or no display at all.Likewise, the administrator may select the type of data that will beprinted as the test results, e.g., quantitative, threshold level, orinterpretative. Additionally, the administrator may select other typesof information to be printed, e.g., operator signature line, subjectsignature line, select the number of copies to be printed, and thespecific printer that will be used to print the test results, e.g.,internal printer, parallel printer, or serial printer. The administratormay also select if the test results will be saved internally within thesystem 100 or externally to, e.g., another computer via an RS232 port.

[0497] If at action block 1410, the user selects the “Operation Mode,”the operator, if previously required by the administrator, enters anoperator ID and password, as well as the subject name and ID (actionblock 1420). Upon correct entry of this information, the operatorselects one of the specific test panels to be run on the system 100(action block 1422). If the operator only desires to collect a samplefor subsequent testing at a laboratory, the operator will select aconfirmatory test. Once a test panel, if any, has been selected, thechemistry cassette 152 is loaded into the test console 102 (action block1424) (See Section II). By virtue of the loading action of the chemistrycassette 152, the buffer drive assembly 1102 is operated to hydrate thedry reagent within the alcohol reagent chamber 1006 of the alcoholreaction assembly 1002, producing and dispensing the alcohol reagentsolution within the alcohol reaction chamber 1004 of the alcoholreaction assembly 1002 (action block 1426) (Section VIII.D). All of thedrive assemblies are then placed into their home position (action block1428). Once the chemistry cassette 152 has been loaded, it is broughtfrom its ambient temperature (10-40° C.) to the optimum operatingtemperature (37° C.) (action block 1430) (See Section IX). At the sametime, the system 100 determines if the chemistry cassette 152 has beenpreviously used (decision block 1432). If the chemistry cassette 152 hasbeen previously used, the cassette loading assembly 300 is operated toeject the chemistry cassette 152 from the test console 102, and thesystem 100, via the user interface 150, informs the operator that thechemistry cassette 152 has been previously used and to load anotherchemistry cassette 152 (action block 1434). If the chemistry cassette152 has not been previously used, the system 100 customizes theoperational parameters of the test console 102 to the specific chemistrycassette 152 and calibrates the test panel (action block 1436) (SeeSection III).

[0498] The sample collection assembly 400 is then operated to collectthe saliva sample from the test subject (action block 1438) (See SectionIV.C). The system 100 determines whether the cassette is a confirmationcassette (decision block 1440). If it is, the confirmation cassette isejected and processed accordingly (action block 1442). It should benoted that if the cassette is a confirmation cassette, action block 1426will not have been completed since there is no test to be run. If thecassette is not a confirmation cassette, the sample is buffered andmixed at action block 1444 (See Section V.C). The sample collectionassembly 400 is then operated to dispense the sample into the flowimmunoassay assembly 600, and specifically, to distribute the sampleamongst the multitude of immunoassay flow paths within the sampledistribution chambers 612, i.e., the sample distribution is performed(action block 1446) (See Section VI.C). Simultaneous with the sampledistribution, the sample/buffer flow assembly 602 of the immunoassayflow assembly 600, and specifically, the buffer drive assemblies 576, isoperated to flow the buffer through the immunoassay flow paths toprepare the immunoassay reaction chambers 616, i.e., the buffer pre-washis performed (action block 1448) (See Section VI.C). During the bufferpre-wash, the optical flow immunoassay scanning assembly 900 is operatedto calibrate the immunoassay flow paths (action block 1450) (See SectionVII.D). During the buffer pre-wash, the alcohol detection assembly 1000is also calibrated by (1) operating the alcohol reader assembly 1004 tomeasure the absorbance of the alcohol reagent solution previouslydispensed within the alcohol reaction chamber 1004; (2) operating thealcohol reaction assembly 1002 to dispense the calibrator solution intothe alcohol reaction chamber 1004 to react with the alcohol reagentsolution and produce the alcohol detectable calibrator solution; and (3)operating the alcohol reader assembly 1004 again to measure theabsorbance of the alcohol detection calibrator solution (action block1452) (See Section VIII.D). The sample/buffer flow assembly 602 of theimmunoassay flow assembly 600, and specifically, the sample driveassemblies 574, is then operated to flow the sample through theimmunoassay flow paths to react within the immunoassay reaction chambers616, i.e., the sample flow is performed (action block 1454) (See SectionVI.C). During sample flow, the optical flow immunoassay scanningassembly 900 is operated to quantitatively detect the presence of anydrug analytes within the sample (action block 1456) (See Section VII.D).During sample flow, the vent/air flow assembly 1016 of the alcoholreaction assembly 1002 is also operated to dispense the sample withinthe alcohol reaction chamber 1004 to react with the alcohol reagentsolution, thereby producing the alcohol detectable sample solution(action block 1458) (See Section VIII.D). The alcohol reader assembly1004 is then operated to quantitatively detect the presence of alcoholwithin the sample (action block 1460) (See Section VIII.D).

[0499] Once the test is complete, the cassette loading assembly 300 isoperated to eject the chemistry cassette 152 from the test console 102,which is then discarded (action block 1462). The system 100 thenanalyzes the collected data (action block 1464), saves the results(action block 1466), and then displays the results of the test (actionblock 1468), and optionally, the operator prints the results (actionblock 1470).

[0500] If at action block 1410, the user selects the “Recall Mode,” theuser enters the specific test to be recalled (action block 1472), andthe system 100 displays the results of the recalled test (action block1474), and optionally, prints the results (action block 1476).

[0501] Although particular embodiments of the present inventions havebeen shown and described, it will be understood that it is not intendedto limit the present inventions to the preferred embodiments, and itwill be obvious to those skilled in the art that various changes andmodifications may be made without departing from the spirit and scope ofthe present inventions. Thus, the present inventions are intended tocover alternatives, modifications, and equivalents, which may beincluded within the spirit and scope of the present inventions asdefined by the claims. All publications, patents, and patentapplications cited herein are hereby incorporated by reference in theirentirety for all purposes.

What is claimed:
 1. A flow immunoassay scanning assembly, comprising: aplurality of immunoassay reaction chambers; a plurality of read cells influid communication with said plurality of immunoassay reactionchambers; a detector having a sensing beam; and a scanning driveassembly configured to translate said detector to intersect saidplurality of read cells with said sensing beam.
 2. The flow immunoassayscanning assembly of claim 1, wherein said detector comprises an opticaldetector.
 3. The flow immunoassay scanning assembly of claim 1, whereineach of said plurality of immunoassay reaction chambers containsfluorescent labeled antigen that is displaced when an analog to saidfluorescent labeled antigen flows through said immunoassay reactionchamber.
 4. The flow immunoassay scanning assembly of claim 1, whereinsaid detector is configured, such that said sensing beam intersects saidplurality of read cells at an angle substantially perpendicular tolongitudinal axes of said read cells.
 5. The flow immunoassay scanningassembly of claim 1, wherein said scanning drive assembly is configuredto translate said detector to repeatedly intersect said plurality ofread cells with said sensing beam.
 6. The flow immunoassay scanningassembly of claim 1, wherein said plurality of read cells comprises fiveor more.
 7. A method of detecting the presence of a plurality of targetanalytes in a sample, comprising: producing a plurality of immunoassayflow paths containing said sample, wherein an analyte indicator isproduced in each of said plurality of immunoassay flow paths in thepresence of a corresponding target analyte; detecting any of saidplurality of analyte indicators in said plurality of immunoassay flowpaths by scanning a sensing beam across said plurality of immunoassayflow paths.
 8. The method of claim 7, wherein said sensing beamcomprises an optical sensing beam.
 9. The method of claim 8, whereinsaid analyte indicator comprises fluorescent labeled antigen.
 10. Themethod of claim 7, wherein said sensing beam is scanned substantiallyperpendicular to the direction of said immunoassay flow paths.
 11. Themethod of claim 7, wherein said sensing beam is scanned repeatedlyacross said plurality of immunoassay flow paths.
 12. The method of claim7, wherein said plurality of immunoassay flow paths comprises five ormore.
 13. The method of claim 7, further comprising outputting aplurality of signals based on said detection of said any analyteindicators within said plurality of immunoassay flow paths.
 14. Themethod of claim 7, further comprising processing said plurality ofsignals to detect the presence of said plurality of target analyteswithin said sample.
 15. The method of claim 7, wherein said sample is asaliva sample.
 16. The method of claim 7, further comprising detecting alocation of each of said plurality of read cells.
 17. The method ofclaim 16, further comprising processing said detected analyte indicatoronly when a location of a corresponding one of said plurality of readcells is detected.
 18. A flow immunoassay scanning assembly, comprising:a plurality of immunoassay reaction chambers; a plurality of read cellsin fluid communication with said plurality of immunoassay reactionchambers; a detector having a sensing beam; a transmitter having anenergy beam; a scan head mechanism to which said detector and saidtransmitter are mounted; and a scanning drive assembly configured totranslate said detector and said transmitter to intersect said pluralityof read cells with said sensing beam and said energy beam.
 19. The flowimmunoassay scanning assembly of claim 18, wherein said detectorcomprises an optical detector, and said transmitter comprises an opticalsource.
 20. The flow immunoassay scanning assembly of claim 19, whereinsaid optical sources comprises a laser.
 21. The flow immunoassayscanning assembly of claim 18, wherein said detector is configured, suchthat said sensing beam intersects said plurality of read cells at anangle substantially perpendicular to longitudinal axes of said readcells; and wherein said transmitter is configured, such that said energybeam intersects said plurality of read cells, such that said energy beamtravels through said read cells at an angle substantially parallel tosaid longitudinal axes of said read cells.
 22. The flow immunoassayscanning assembly of claim 18, wherein said scanning drive assembly isconfigured to translate said detector and said transmitter to repeatedlyintersect said plurality of read cells with said sensing beam and saidenergy beam.
 23. The flow immunoassay scanning assembly of claim 18,wherein said plurality of read cells comprises five or more.
 24. Theflow immunoassay scanning assembly of claim 18, further comprising aread cell detector fixably coupled to said scan head mechanism andconfigured to sense a location of each of said plurality of read cells.25. The flow immunoassay scanning assembly of claim 24, furthercomprising processing circuitry for processing an output of saiddetector only when said read cell detector senses said location of eachof said plurality of read cells.
 26. The flow immunoassay scanningassembly of claim 24, further comprising a plurality of read cellindicators, each of which is spaced from an adjacent read cell indicatora distance equal to a distance in which each read cell of said pluralityof read cells is spaced from an adjacent read cell, wherein said readcell detector senses said location of said read cells by sensing saidplurality of read cell indicators.
 27. The flow immunoassay scanningassembly of claim 26, wherein said plurality of read cell indicatorscomprises a plurality of notches.
 28. The flow immunoassay scanningassembly of claim 18, wherein said scanning drive assembly comprises: arail that extends substantially perpendicularly along said plurality ofread cells; and a runner on which said scan head mechanism is fixablycoupled, and being configured to translate said scan head mechanismalong said rail.
 29. A method of detecting the presence of a pluralityof target analytes in a sample, comprising: producing a plurality ofimmunoassay flow paths containing said sample, wherein an analyteindicator is produced in each of said plurality of immunoassay flowpaths in the presence of a corresponding target analyte; exciting saidplurality of analyte indicators by scanning an energy beam across saidplurality of immunoassay flow paths; and detecting any of said pluralityof excited analyte indicators in said plurality of immunoassay flowpaths by scanning a sensing beam across said plurality of immunoassayflow paths.
 30. The method of claim 29, wherein said sensing beamcomprises an optical sensing beam, and said energy beam comprises anoptical energy beam.
 31. The method of claim 30, wherein said opticalenergy beam comprises a laser beam.
 32. The method of claim 31, whereinsaid analyte indicator comprises fluorescent labeled antigen.
 33. Themethod of claim 29, wherein said sensing beam is scanned substantiallyperpendicular to the direction of said immunoassay flow paths, and saidenergy beam is scanned substantially parallel to the direction of saidimmunoassay flow paths.
 34. The method of claim 29, wherein said sensingbeam and said energy beam are simultaneously scanned across saidplurality of immunoassay flow paths.
 35. The method of claim 29, whereinsaid sensing beam and said energy beam are both scanned repeatedlyacross said plurality of immunoassay flow paths.
 36. The method of claim29, wherein said plurality of immunoassay flow paths comprises five ormore.
 37. The method of claim 29, further comprising outputting aplurality of signals based on said detection of said any excited analyteindicators within said plurality of immunoassay flow paths.
 38. Themethod of claim 29, further comprising processing said plurality ofsignals to detect the presence of said plurality of target analyteswithin said sample.
 39. The method of claim 29, wherein said sample is asaliva sample.
 40. The method of claim 29, further comprising detectinga location of each of said plurality of read cells.
 41. The method ofclaim 40, further comprising processing said detected analyte indicatorwhen a location of a corresponding one of said plurality of read cellsis detected, and not processing said detected analyte indicator when alocation of said corresponding one of said plurality of read cells isdetected.